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Biomedical subjects

N Stern

Publications and source records attributed to N Stern.

At least 37 records · Page 2Linked to original sources
PubMed2000

Risk factor clustering in hypertensive patients: impact of the reports of NCEP-II and second joint task force on coronary prevention on JNC-VI guidelines.

INTRODUCTION: Although the association of hypertension with established risk factors has been noted in several population studies, the recent redefinition of dyslipidaemia, hypertension and diabetes calls for reassessment of the prevalence and pattern of risk factor clusters in essential hypertension. OBJECTIVE: To analyse the risk factor profile of Israeli patients with essential hypertension seen by primary care physicians and in hypertension specialty clinics, based on current definitions of dyslipidaemia hypertension and diabetes and JNC-VI guidelines for the assessment of risk factors. DESIGN AND SETTING: We analysed the risk profile of 324 Israeli hypertensive subjects using the JNC-VI risk table and risk grouping. A total of 122 consecutive patients were recruited from primary care clinics and 212 consecutive patients were recruited from a hospital based hypertension clinic. RESULTS: Amongst hypertensive individuals with no known target organ damage, only 1.5% had no risk factors other than hypertension, whereas all hypertensives with coronary artery disease had additional risk factors. Of the six listed major JNC-VI risk factors (smoking, dyslipidaemia, diabetes, age, sex, family history of cardiovascular disease), hypertensive subjects without coronary artery disease (coronary artery disease-negative) had 3.02 +/- 0.10 risk factors, whereas hypertensive subjects with coronary artery disease (coronary artery disease positive) had 3.6 +/- 0.07 risk factors other than hypertension (P < 0.01). Dyslipidaemia defined by NCEP-II criteria was the most common associated risk factor identified in 93% of coronary artery disease-positive and 77% of the coronary artery disease-negative hypertensive subjects. The most common dyslipidaemic abnormality was an increased LDL cholesterol (79.2% of the cohort), followed by hypertriglyceridaemia (31.7%) and low HDL cholesterol (22.3%). Nevertheless, in nearly half of the coronary artery disease-negative patients, LDL cholesterol concentrations were within 30 mg dL-1 of the target levels. The most common dyslipidaemic variant was isolated hypercholesterolaemia (42%), whereas the syndrome X dyslipidaemic combination of hypertriglyceridaemia and low HDL was strikingly uncommon, observed in 2.8% of the coronary artery disease-positive and 0.8% of the coronary artery disease-negative patients. CONCLUSIONS: (i) JNC-VI group risk A patients (no risk factors) comprise a very small minority in this cohort (< 5%); (ii) dyslipidaemia is exceedingly common with mild hypercholesterolaemia being the most prevalent variant and hypertriglyceridaemia with low HDL the least common form.

Cardiovascular Diseases↗
PubMed2000

Effect of prefabricated metal post-head design on the retention of various core materials.

Retention of various post heads to core restorative materials is an important factor in the selection of prefabricated post systems and restorative materials for the restoration of endodontically treated teeth. This study examines the retention of a post-core prefabricated system in relation to core material and post-head design. A total of 60 samples were prepared using two different post systems (ParaPost Plus (PP) and ParaPost Unity (PU), with amalgam, composite or glass-ionomer as one of the core materials. The samples were tested using the Instron testing machine. The PP was superior to the PU prefabricated post with respect to the retention of various core materials. Retention values in descending order of magnitude were found to be: composite, amalgam and glass-ionomer (significantly lower). The rhomboid serrated design of PP was superior in retention to the rounded smooth UP system. Composite material proved to be superior in retention, closely followed by amalgam, with glass-ionomer significantly less retentive.

Analysis of Variance↗
PubMed2000

Trauma history as a predictor of psychologic symptoms in women with breast cancer.

PURPOSE: To identify predictors of psychiatric problems in women with early-stage breast cancer. PATIENTS AND METHODS: One hundred sixty women with early-stage breast cancer were recruited from three treatment centers. They filled out self-report questionnaires, including a medical history and demographic survey, the Trauma History Questionnaire, Life Event Questionnaire, Brief Symptom Inventory, Beck Depression Inventory, and Duke-UNC Functional Social Support Questionnaire, and were evaluated using the Structured Clinical Interview for DSM-III-R. RESULTS: Hierarchical regression analyses indicated that four of five variable sets made a significant incremental contribution to outcome prediction, with 35% to 37% of the variance explained. Outcomes were predicted by demographic variables, trauma history variables, precancer psychiatric diagnosis, recent life events, and perceived social support. Cancer treatment variables did not predict outcome. CONCLUSION: The findings highlight the important roles of trauma history and recent life events in adjustment to cancer and have implications for screening and treatment.

Adult↗
PubMed1999

Contaminant eluted from solid-phase plasmid affinity-purification protocol columns is not found using liquid-phase methods and can be prevented.

The preparation of high quality plasmid DNA is a necessary requirement for most molecular biology applications. We compared four different large plasmid preparation protocols, which were based on either a liquid-phase approach (Triton lysis) or purification of alkaline lysis bacterial extracts followed by supercoiled plasmid purification on affinity columns. Two host Escherichia coli strains, JM 109 and INValphaF', were used to grow the test plasmids for comparison of product plasmid DNA produced from the four different plasmid isolation methods. While the DNA grown in E. coli strain JM109, prepared by liquid-phase Triton lysis was appropriately restricted by 12 restriction enzymes, this was not the case for any of the JM109-grown DNA purified by any of the affinity column solid-phase approaches. In contrast to this, when the plasmid DNA was grown in E. coli strain INValphaF', most restriction enzymes cut DNA appropriately, irregardless of the plasmid preparation protocol used. It seems that an impurity commonly eluted with the DNA from all three of the solid-phase DNA columns had an equal effect on the above enzymes using the common host strain JM109, but not strain INValphaF'.

Chromatography, Affinity↗
PubMed1999

TRH is a tonic secretagogue in growth hormone secreting but not in nonfunctioning pituitary tumors.

In most patients with growth hormone (GH) secreting pituitary adenomas and clinically nonfunctioning pituitary tumors (NFPT) the intravenous injection of thyrotropin releasing hormone (TRH) augments the secretion of GH and subunits of gonadotropin hormones respectively. Similar hormone responses to TRH have been detected in rat pituitary cell lines and in primary human pituitary tumor cultures in vitro. Nevertheless the TRH effect on tumor hormonal secretion has not been well characterized. In the present study we examined TRH-induced hormone secretion in GH secreting tumors and in NFPT in vitro. Cultured cells secreted betaLH and betaFSH (NFPT) or GH (GH secreting adenomas) up to 14 days in culture. In NFPT TRH (10(-8) mol/l) elicited peak betaLH and betaFSH secretion at 60 to 90 min, with no further increase at 24 h. TRH-stimulated GH secretion peaked at 90-120 min, and decreased after 3 h, but a secondary rise occurred after 24 h of incubation. Chronic daily exposure to TRH followed by an acute TRH challenge resulted in a further increase of GH secretion after one hour. In contrast, acute TRH administration following chronic exposure did not elicit increased P-subunits secretion in NFPT. Coadministration of cycloheximide did not change TRH induced beta-subunits secretion in NFPT. However, when it was administered 24 h prior to TRH, it blocked both basal and TRH induced beta-subunits levels in NFPT. Cycloheximide had no effect on basal or stimulated GH secretion when administered concomitantly or 24 h before TRH. Incubation of cultured GH secreting tumors with cycloheximide during 5 days blocked both basal and TRH stimulated GH secretion, thus indicating dependency on protein synthesis during the chronic, secondary phase. Since the acute secretion was not affected by coadministration of cycloheximide, these early increases in hormone levels apparently reflect the release of stored hormone. In summary, GH secreting adenomas and NFPT differ significantly in their hormonal response to continuous exposure to TRH. The mechanisms underlying the sustained effect of TRH on GH secretion in vitro remain to be investigated. If endogenous TRH exerts a similar continuous effect it may contribute to the disregulated GH secretion in acromegaly.

Adenoma↗
PubMed1999

Platelet-derived endothelial cell growth factor inhibits DNA synthesis in vascular smooth muscle cells.

Platelet-derived endothelial cell growth factor (PD-ECGF) is linked to angiogenesis in human cancer. Direct studies have demonstrated that PD-ECGF is a potent mitogen for endothelial cells in vivo. Because endothelial repair and smooth muscle cell proliferation are two processes that affect arterial wall structure and tone, we analyzed the effects of PD-ECGF on DNA synthesis and creatine kinase BB-specific activity (CK) in human umbilical artery smooth muscle cells (SMC) and in a human umbilical endothelial cell line (E304). In SMC, PD-ECGF (0.001 to 10 U/mL) inhibited DNA synthesis dose dependently (-24% + 6% to -63% + 15%) assessed by 3[H]thymidine incorporation into DNA, whereas in E304 it stimulated DNA synthesis dose dependently (30% + 4% to 100% + 4%). In both SMC and E304, however, PD-ECGF elicited an increase in CK-specific activity by 54% to 130% and 79% to 163%, respectively. These effects were reversed by a specific anti-PD-ECGF antibody. In E304 cells PD-ECGF enhanced 17beta-estradiol (E2) or dihydrotestosterone (DHT)-induced DNA synthesis from 56% to 122% and from 127% to 359%, and CK activity from 70% to 180% and from 90% to 190%, respectively. In SMC PD-ECGF, an inhibitor of 3[H]thymidine incorporation by itself, markedly enhanced the stimulatory effect of low concentrations of E2 and DHT on 3[H]thymidine incorporation. It also increased E2 and DHT CK induction from 40% to 140% and from 52% to 120%, respectively. In both E304 and SMC, PD-ECGF inhibited the proliferative and the CK-inducing effects of platelet-derived growth factor (PDGF) and immunoglobulin F1 (IGF1). Thus, PD-ECGF, an established growth promoter for endothelial cells, is a potent inhibitor of DNA synthesis in human arterial SMC. However, in both E304 endothelial cells and SMC, PD-ECGF enhances the stimulatory effect of low concentrations of gonadal steroids on 3[H]thymidine incorporation. PD-ECGF antagonizes PDGF- and IGF1-induced DNA synthesis in both E304 and SMC cells. By inhibiting arterial SMC proliferation and accelerating endothelial cell replication, PD-ECGF may buffer the effect of PDGF and favorably modulate arterial wall response to injury.

Cell Division↗
PubMed1999

Thyroxine replacement therapy enhances clearance of chylomicron remnants in patients with hypothyroidism.

To further confirm the benefit of replacement therapy in terms of risk for coronary artery disease, we evaluated the effect of T4 on postprandial lipoproteins in patients with hypothyroidism. Nine normolipidemic patients (aged 62.75+/-7.6 yr) with TSH of 32.2+/-13.2 mU/L and free T4 of 0.66+/-0.17 ng/mL were treated with T4 (50-100 microg/day) for at least 4 months. The behavior of postprandial lipoproteins was assessed before and during treatment by determining retinyl palmitate levels in the total plasma, chylomicrons (Sf >1000) and chylomicron remnants (Sf <1000) fractions for 8 h after a mixed meal plus vitamin A. During T4 treatment, serum levels of TSH and FT4 were 4.4+/-4.9 mU/L and 1.2+/-0.34 ng/mL (P = 0.001 and P = 0.002), respectively. Fasting low density lipoprotein cholesterol decreased from 166+/-35 to 135+/-23 mg/dL (P = 0.035). Retinyl palmitate (RP) levels in the chylomicron remnant fraction was reduced significantly during therapy from 6948+/-2790 to 5174+/-2401 microg/L x h (area under the curve +/-SD; P = 0.014). Total plasma RP and chylomicron RP remained unchanged. We conclude that T4 enhances the clearance of chylomicron remnants in normolipidemic patients with hypothyroidism.

Cholesterol, HDL↗
PubMed1999

Effect of TRH on beta-gonadotropin subunits in patients with pituitary microincidentalomas.

OBJECTIVE: To explore the hypothesis that most of the pituitary abnormalities compatible with the diagnosis of microadenoma, and detected in about 10% of the normal adult population, represent asymptomatic gonadotropinomas. DESIGN: Patients diagnosed with pituitary microincidentalomas at the Institute of Endocrinology of the Tel Aviv Medical Center were evaluated. Circulating beta-subunits of gonadotropin hormones were measured before and 30, 45, 60 and 90 min after the intravenous injection of 400 microgram TRH. PATIENTS: Twenty-two patients with pituitary incidentaloma and 16 normal volunteers were tested. RESULTS: In 16 of the 22 patients, an abnormal beta-subunit response was detected after the TRH challenge. Three patients had an abnormal increase in both beta-FSH and beta-LH after TRH administration. Isolated pathological beta-FSH or beta-LH responses were demonstrated in five and eight patients respectively. Six patients had normal basal and stimulated gonadotropin subunit values, raising the possibility that their lesions were not pituitary microadenomas. There was a significant overall difference between the response to TRH of the patient and control groups. In the gonadotropin positive group, comprising 16 patients, serum beta-FSH increased from 6.4+/-1.6 ng/ml to 9.2+/-1.3 ng/ml (P=0.042) 1 h after TRH stimulation, whereas no changes were detected in the control group after TRH injection (basal: 4.1+/-0.8 ng/ml, peak: 5.1+/-0.8 ng/ml; P=0.15). Serum beta-LH increased from 10.5+/-3.2 ng/ml to 23.4+/-4.9 ng/ml (P=0.0037) at this time, in contrast to a lack of response in controls (basal: 6.4+/-1.5 ng/ml, peak: 8.2+/-2.3 ng/ml; P=0.24). CONCLUSION: In about 73% of patients with pituitary incidentalomas smaller than 10 mm, TRH elicits an increase in gonadotropin beta-subunits. This observation raises the possibility that non-functioning pituitary micro- and macroadenomas, which share a similar response to TRH, originate in a common ancestor cell type, probably a pituitary gonadotrope.

Adenoma↗
PubMed1999

Pregnancy decreases immunoreactive parathyroid hormone level in rats with chronic renal failure.

Normal pregnancy is associated with an increase in serum parathyroid hormone and 1,25-dihydroxyvitamin D3 (calcitriol). The effect of pregnancy on these hormones in chronic renal failure (CRF) is unknown. The present work was undertaken to study the changes of serum immunoreactive parathyroid hormone (iPTH) and calcitriol in pregnant rats with CRF. The following experimental groups were studied: CRF1 (5/6 nephrectomized virgin female rats), CRF2 (5/6 nephrectomized pregnant rats at day 20-21 of pregnancy), CRF3 (5/6 nephrectomized rats 2 weeks after delivery) and their respective sham-operated control groups: N1, N2 and N3. The 5/6 nephrectomy (CRF1) resulted in renal failure with very high serum iPTH (100+/-18 pg/ml) and low calcitriol levels (10.6+/-4.3 pg/ml) compared with normal rats [N1: 14+/-2.5 pg/ml (P<0.001) and 18.2+/-4.2 pg/ml (P<0.01) respectively]. The pregnancy in CRF rats (CRF2) resulted in normalization of serum iPTH levels (18.2+/-5.41 pg/ml), which was associated with a parallel increase in serum calcitriol (29.4+/-8.0 pg/ml) similar to that in pregnancy of normal rats (N2). Two weeks after delivery the CRF rats (CRF3) once again had high serum iPTH (87+/-17 pg/ml) and low calcitriol levels (9.3+/-1.2 pg/ml), similar to those observed in non-pregnant uraemic rats (CRF1). It is concluded that pregnancy decreases serum iPTH in 5/6 nephrectomized CRF rats most probably by the increased level of calcitriol synthesized by the feto-placental unit.

Analysis of Variance↗
PubMed1998

Fluorescence derivatisation of urinary corticosteroids for high-performance liquid chromatographic analysis.

Corticosteroids containing a C21 primary hydroxyl group were derivatised with 9-anthroyl cyanide. The reagent was prepared as a solution in acetonitrile, containing 0.1% triethylamine, at a concentration of 2 mg/ml. Approximately 1 microg of corticosteroid was reacted with 100 microl of this reagent, at 45 degrees C for 2 h. The fluorescent derivatives were separated by HPLC on a silica column, 250x4.6 mm I.D., by stepwise elution, with a mobile phase of 2-propanol-hexane (2:98) for 20 min, followed by 2-propanol-hexane (7:93) from 20 to 40 min. The fluorescence detector was set to 370-nm excitation and 470-nm emission. The relatively low temperature for derivatisation avoided reaction with secondary hydroxyl groups and also prevented thermal degradation of the corticosteroids.

Adrenal Cortex Hormones↗
PubMed1998

Increased body weight associated with prolactin secreting pituitary adenomas: weight loss with normalization of prolactin levels.

OBJECTIVE: Hyperprolactinaemia in humans may be associated with a high prevalence of obesity but the nature of this link is poorly defined. The aim of this study was to establish the relationship between hyperprolactinaemia and body weight in patients with prolactin-secreting pituitary tumours. DESIGN: We conducted a retrospective study of prolactinoma patients treated at the Endocrine Institute of the Tel Aviv Medical Center, Israel, during the period 1989-1996. Patients with clinically non-functioning pituitary macroadenomas (NFA) served as the control group. Data on demographic parameters, body weight before and during treatment, clinical presentation including history of weight fluctuations, tumour size as measured by computed tomography or magnetic resonance imaging, modalities and response to treatment, and pituitary function before and during treatment were recorded from medical files. PATIENTS: Forty-two patients with prolactinomas (PR) and 36 patients with clinically non-functioning macroadenomas (NFA) comprised the study population. RESULTS: Mean weight was 93 +/- 3.4 kg and 78 +/- 2.7 kg in male patients with PR and NFA respectively (P = 0.0007). Recent weight gain (8 to 22 kg) was a presenting symptom in 13 PR patients, whereas only one NFA patient had this clinical presentation (P = 0.001). Seventeen PR patients lost weight (mean change -8.3 +/- 1.5 kg, range -2-28 kg), during prolactin lowering therapy, 11 of whom had entirely normalized prolactin levels. Fourteen of the 18 patients who did not lose weight still had elevated prolactin levels (P = 0.01). Weight loss in patients with PR could not be attributed to altered pituitary function nor to compression of the third ventricle. In contrast to PR, no significant weight loss was observed in NFA patients. CONCLUSION: Weight gain and elevated body weight are frequently associated with prolactinomas regardless of a mass effect on the hypothalamus or pituitary function. In this series, weight loss was recorded in 70% of prolactinomas patients and in 90% of male patients who normalized their prolactin levels. We propose the inclusion of hyperprolactinaemia in the differential diagnosis of endocrine obesity and weight gain.

Adult↗
PubMed1998

The use of beta-subunits of gonadotrophin hormones in the follow-up of clinically non-functioning pituitary tumours.

OBJECTIVE: Clinically nonfunctioning pituitary adenomas (NFA) are mostly of gonadotroph origin. However, increased levels of circulating hormones or subunits in patients with NFA usually do not cause clinical symptoms, nor are they used as biological tumour markers. In this study we assessed the value of measuring beta subunits of gonadotrophin hormones in the post-operative follow-up of patients bearing these tumours. DESIGN: Patients harbouring NFA were studied before and three months after transphenoidal pituitary surgery. beta-LH and beta-FSH levels were measured before and following TRH administration on the two occasions. Hormone levels were analyzed in relation to imaging studies performed before and after surgery. PATIENTS: Twenty four patients operated at the Tel Aviv-Sourasky Medical Centre for NFA. RESULTS: Pathological beta-FSH and beta-LH levels were detected in 79% and 60% of patients respectively. beta-LH levels decreased after surgery but there were no significant changes in beta-FSH levels. There was a tendency for tumours with high basal beta-LH levels to be larger and to have a poor surgical outcome. Normalization of beta-LH levels post-operatively was usually associated with a decrease in tumour mass or complete removal of the tumour. Persistent pathological responses of beta-LH to TRH after surgery were common in patients with residual tumours on imaging. Nevertheless there were exceptions to this pattern, rendering post-operative beta-LH levels insufficiently reliable as a marker for the presence of residual tumour. CONCLUSION: Although there appears to be a relationship between beta-LH levels, tumour size and surgical outcome, this association is presently insufficient to allow the routine use of either basal or TRH induced beta-LH responses in the post-surgical follow-up of clinically nonfunctioning pituitary adenomas.

Adenoma↗
PubMed1998

Bond strength of photocured composite resin facings: clinical versus laboratory procedures.

The tensile strengths of laboratory versus clinical photocured composite resins have been investigated. Metal surfaces were bonded to photocured composite resin by either retentive beads, Sebond or Silicoating. The bond strengths were measured by an Instron machine and the fracture sites observed. Following repair with the adhesives Dentacolor Opaquer, Fusion and Cover up 2, the Instron measurements were repeated. The metal/facing bond strength was the highest in samples fabricated by the Silicoating technique, the bond strength exceeding the cohesive forces in the composite resin facing. The tensile strengths of metal/facing bonded by Sebond and retentive beads were similar. Fractures that include the facing and partially reveal the metal are the least resistant to tension after repair. Renewal of the Opaque layer and completion of the facing is superior to any of the repair methods used in this paper. The original fracture point is the weakest after repair. All the repair kits tested were inferior to the original restoration materials.

Adhesiveness↗
PubMed1998

Effects of gonadal steroids and their antagonists on DNA synthesis in human vascular cells.

The cardiovascular effect of estrogen is currently under intense investigation, but the role of androgens in vascular biology has attracted little attention. Because endothelial repair and vascular smooth muscle cell (VSMC) proliferation affect atherogenesis, we analyzed the effects of 17beta-estradiol (E2), dihydrotestosterone (DHT), and sex hormone antagonists on DNA synthesis in human umbilical VSMCs and in E304 cells (a human umbilical endothelial cell line). In VSMCs, both E2 and DHT had a biphasic effect on [3H]thymidine incorporation into DNA: low concentrations (0.3 nmol/L for E2, 3 nmol/L for DHT) stimulated [3H]thymidine incorporation (+35% and +41%, respectively), whereas high concentrations (30 nmol/L for E2, 300 nmol/L for DHT) inhibited [3H]thymidine incorporation (-40%). In contrast, E2 (0.3 to 300 nmol/L) and DHT (3 to 3000 nmol/L) dose-dependently enhanced [3H]thymidine incorporation in E304 cells (peak, +85% for both). In VSMCs, high concentrations of E2 and DHT inhibited platelet-derived growth factor (PDGF)-or insulin-like growth factor (IGF-1)-induced DNA synthesis (-50% to 80%), whereas PDGF- or IGF-1-dependent DNA synthesis in E304 cells was further increased by E2. The antiestrogens tamoxifen and raloxifene mimicked the effects of E2 on DNA synthesis in both VSMCs and E304 cells. However, when coincubated with a stimulatory concentration of E2 (0.3 nmol/L), tamoxifen and raloxifene blocked E2-induced [3H]thymidine incorporation in E304 cells but not in VSMCs. Finally, the androgen antagonist flutamide inhibited the biphasic effects of DHT on VSMCs and blocked the increase in DNA elicited by DHT in E304 cells. The results suggest complex, dose-dependent, and cell-specific interactions of estrogens, androgens, and their respective antagonists in the control of cellular proliferation in the vascular wall. Gonadal steroid-dependent inhibition of VSMC proliferation and stimulation of endothelial replication may contribute to vascular protection and remodeling responses to vascular injury.

Analysis of Variance↗
PubMed1997

[Follow-up and therapy of acute colchicine poisoning].

Colchicine poisoning is a rare event. Its outcome is, compared to other drug intoxications, often serious or even fatal. Intaxications with colchicine may occur by ingestion of tablets as well as by consumption of meadow saffron leaves (Colchicum autumnale) that are often mistakenly collected instead of the leaves of ramson herb (Allium ursinum). Colchicine poisoning typically shows three phases: initially gastrointestinal symptoms predominate, in the second phase multiorgan failure may occur possibly leading to death. In case the patient survives, the third phase of recovery follows during which the patients often present with hair loss. The fatal dose of acute colchicine poisoning is estimated at about 0.9 mg/kg. Since hemodialysis and hemoperfusion are not effective measures because of the high volume of distribution, an aggressive primary decontamination with gastric lavage and activated charcoal is required as early as possible. A promising new aspect in the treatment of heavy colchicine overdose is the immunotherapy with colchicine-specific fab-fragments. At present this treatment is still in an experimental stage and has been applied so far to one patient with beneficial effects. Unfortunately colchicine-specific antibodies are not yet commercially available.

Adult↗
PubMed1997

Combined beta FSH and beta LH response to TRH in patients with clinically non-functioning pituitary adenomas.

OBJECTIVE: 'Paradoxical' responses of LH, FSH, alpha-subunits and beta LH to TRH have previously been reported in individuals with clinically non-functioning pituitary tumours (NFT). The present study was designed to assess the in vivo and in vitro responses of beta FSH to TRH in NFT. We further examined the possibility that a TRH challenge with combined measurement of beta FSH and beta LH will identify a common anomalous secretory pattern in patients with NFT. DESIGN, PATIENTS AND MEASUREMENTS: Forty patients with NFT underwent a standard TRH test (400 micrograms intravenously). Blood samples for the determination of beta FSH, beta LH, FSH and LH were collected prior to TRH as well as 15, 30, 45, 60 and 90 minutes following injection. Additionally, cultured adenomatous cells from eight to these patients were exposed to TRH in the absence and presence of octreotide and gonadotropin subunits were determined. RESULTS: TRH elicited a marked rise in circulating beta FSH in 29 of 40 individuals and in beta LH in 28 of 36 patients with NFT. In a subgroup of eight individuals whose tumours were harvested during surgery and cultured for 7-21 days, TRH increased beta FSH or beta LH and alpha-subunit release in cultured adenomatous cells in all cases, including tumours from subjects not responding to TRH in vivo. In this subgroup of patients octreotide inhibited basal beta FSH secretion but not basal beta LH secretion both in vivo and in primary cultures of NFT cells. Both the in vivo and in vitro beta FSH, beta LH and alpha-subunit responses to TRH were entirely inhibited by octreotide. In all, 38 of the 40 subjects could be identified by either elevated basal beta FSH or beta LH levels and/or an abnormal rise in either beta FSH or beta LH in response to TRH. CONCLUSION: The measurement of basal and TRH-stimulated beta-FSH and beta-LH levels identifies an abnormal hormonal secretory pattern in the vast majority (> 90%) of patients with clinically nonfunctioning pituitary tumours.

Adenoma↗