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Biomedical subjects

D Thomson

Publications and source records attributed to D Thomson.

At least 37 records · Page 2Linked to original sources
PubMed1988

The cryopreserved homograft valve in the pulmonary position: early results and technical considerations.

Since September, 1985, 20 patients have undergone implantation of a homograft valve in the pulmonary position (16 pulmonary, 4 aortic). There were 11 primary operations and 9 reoperations. In 7 of 11 primary operations the homograft valve was utilized as a composite conduit with a short Dacron extension. In four of five reoperations for a failed porcine valved conduit, a composite homograft conduit was used. Four patients underwent implantation of a free homograft in a previously repaired right ventricular outflow tract (RVOT). Age ranged from 15 days to 22 years. There was one operative death (5%), a seven-week-old infant with truncus arteriosus. Long-term follow-up ranges from 1 to 30 months. Clinical performance has been satisfactory in 18 of 19 patients. One patient undergoing free implantation of a pulmonary valve in the RVOT required replacement at 18 months with a porcine valve. In this patient, pulmonary insufficiency was caused by distortion of the annulus secondary to dilatation and pulmonary hypertension. Nine of 18 survivors do not require medication. Eleven of 18 have trivial to mild pulmonary insufficiency murmurs without symptomatology. The homograft valve is extremely useful in reconstruction of the right heart, however, early insufficiency murmurs have been noted. Distortion of the valve annulus may contribute to the early onset of a benign insufficiency murmur. Residual distal obstruction or pulmonary hypertension may be a contraindication to the use of a free homograft in the orthotopic position.

Adolescent↗
PubMed1988

A prospective study of cisplatin-based combination chemotherapy in advanced germ cell malignancy: role of maintenance and long-term follow-up.

Two hundred fifty-three patients with advanced germ cell malignancy received initial chemotherapy with cisplatin, vinblastine, and bleomycin followed by surgical resection of residual masses if possible. Patients achieving complete remission (CR) were prospectively randomized to receive 6 months maintenance therapy with vinblastine or no further treatment. CR was achieved in 183 patients (72%) and a further eight patients (4%) had complete resection of residual viable malignancy (no evidence of disease [NED]). Pretreatment factors having a significant adverse influence on response by univariate analysis included extragonadal origin of the tumor, poor performance status, advanced lung or lung and abdominal disease, and elevated serum levels of human chorionic gonadotropin (HCG) and alpha-fetoprotein (AFP) greater than 1,000 ng/mL. Multivariate regression analysis indicated the independent prognostic factors of significance were advanced lung or advanced lung and abdominal disease, total tumor diameter greater than 10 cm, and a serum level of HCG greater than 1,000 ng/mL. Of the toxicities encountered, myelosuppression was significant, being exacerbated by radiotherapy, and seven deaths occurred from septicemia. Bleomycin pulmonary toxicity occurred in 46% of patients and was severe in 4%, resulting in eight deaths. With a median follow-up of 64 months, relapses have occurred in 25 patients with no significant difference between those patients receiving or not receiving maintenance vinblastine. Eight of these relapses occurred beyond 1 year and four beyond 2 years of follow-up. Presently, 68% of the total patient population is alive and disease-free, with 84% of the CR and NED patients alive and 81% alive and disease-free. It is concluded that with prolonged follow-up, vinblastine maintenance therapy does not improve treatment outcome. Moreover, late relapses occur, cautioning against premature pronouncements of cure.

Adolescent↗
PubMed1987

Reflux patterns following limited myotomy without fundoplication for achalasia.

Five patients with achalasia underwent limited myotomy without fundoplication. Surgery reduced mean lower esophageal sphincter resting pressure significantly (p less than .05) from 31 +/- 9.7 mm Hg to 16.1 +/- 8.2 mm Hg. Twenty-four-hour ambulatory esophageal pH studies demonstrated that the percentage of time the pH in the distal esophagus was below 4 was similar whether the patient was upright or supine (6.6 +/- 6.5% of total time upright vs. 9.1 +/- 12.7% of total time). Reflux events that occur in the supine position may be significant because of their prolonged duration resulting from the absence of normal secondary peristalsis in the body of the esophagus. Patients with achalasia who have undergone esophagomyotomy without fundoplication do not appear to experience more reflux than control subjects with normal esophageal function.

Adolescent↗
PubMed1987

Hemodynamic effects of dopamine during thoracic epidural analgesia in man.

The cardiovascular effects of dopamine were studied before and during thoracic epidural analgesia (TEA) in eight patients prior to abdominal aortic surgery. Dopamine was infused at rates of 2, 4, and 8 micrograms X kg-1 X min-1. Mean plasma dopamine concentration increased proportionally to the infusion rate. Before TEA, dopamine 8 micrograms X kg-1 X min-1 decreased systemic vascular resistance 4 +/- 4 mmHg min X 1-1 (m +/- SD) (P less than 0.05), but increased mean arterial pressure 15 +/- 12 mmHg (P less than 0.01), cardiac output 1.9 +/- 1.0 1 X min-1 (P less than 0.01), heart rate 10 +/- 9 beats X min-1 (P less than 0.05), and plasma norepinephrine concentration 544 +/- 252 pg X ml-1 (P less than 0.01). After the induction of TEA, which extended above the T2 dermatome and below the L2 dermatome, saline and albumin were infused to maintain central venous and pulmonary capillary wedge pressures. TEA reduced mean arterial pressure from 96 +/- 18 to 55 +/- 8 mmHg (P less than 0.01), cardiac output from 4.7 +/- 0.9 to 3.9 +/- 0.9 1 X min-1 (P = 0.05), systemic vascular resistance from 21 +/- 6 to 14 +/- 3 mmHg min X 1-1 (P less than 0.05), and plasma norepinephrine concentration from 394 +/- 141 to 207 +/- 73 pg X ml-1 (P less than 0.01). The plasma epinephrine concentration was reduced 49% after the induction of TEA.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Diffuse proliferative glomerulonephritis--how many types?

Fifty-four biopsies of diffuse proliferative glomerulonephritis were subdivided into two groups, diffuse endocapillary proliferative glomerulonephritis (DEPGN) and mesangial proliferative glomerulonephritis (MPGN) according to current morphological criteria. The two groups were then compared by light microscopy, cell counting techniques, electron microscopy, immunofluorescence or immunoperoxidase techniques, and a clinical survey. The results show that DEPGN differs from MPGN in only three points: (1) the former has a greater degree of mesangial proliferation, (2) the former has a less favourable short-term prognosis and (3) large subepithelial deposits (humps) are much more common in DEPGN than in MGPN (in this series no MPGN cases showed such deposits), while small dark deposits are present in or on the glomerular capillary basement membrane in more cases of MPGN than of DEPGN. It is proposed that biopsies showing diffuse proliferation of mesangial cells should be classified as diffuse proliferative glomerulonephritis of a mild, moderate or severe degree, as the current classification has been interpreted as implying separate aetiologies and suggests that these are two distinct disease entities.

Biopsy↗
PubMed1987

Phase I study of epirubicin given on a weekly schedule.

Epirubicin was studied in a phase I setting to find the maximum tolerated dose when given weekly for 3 of 4 weeks. Forty-one evaluable patients were treated in groups at doses increasing from 20 to 45 mg/m2. The highest dose level produced the maximum degree of myelosuppression (lowest neutrophil count, 1.9 X 10(9)/L; range, 0-3.7) recorded on Day 22. This was well-tolerated in this group of mainly pretreated patients. Nonhematologic side effects were minimal. This dose schedule allows a greater dose per unit time to be administered than other recommended schedules for epirubicin.

Adult↗
PubMed1986

Haemodynamic effects of pretreatment with metoprolol in hypertensive patients undergoing surgery.

Thirty hypertensive patients scheduled for cholecystectomy or hernia repair under general anaesthesia with thiopentone-fentanyl-nitrous oxide-pancuronium were divided into two groups of 15. One group received metoprolol tablets 200 mg in a slow release form, once daily for at least 2 weeks including the morning of surgery. In addition, metoprolol 15 mg was injected i.v. shortly before the induction of anaesthesia. The other group received placebo tablets and saline. Two patients in the treatment group and one patient in the placebo group were subsequently excluded, because of complications during treatment. Metoprolol significantly reduced arterial pressure both during undisturbed anaesthesia, during intubation and after extubation. A similar tendency was observed also during surgery, although it was not quite significant (P = 0.055). However, metoprolol had no effect on variations in systemic vascular resistance. Mean pulmonary arterial pressures during anaesthesia and surgery were significantly greater in the control, than in the metoprolol, group. Central venous pressure (CVP) and pulmonary arterial occlusion pressure (PAOP) increased significantly in both groups in response to the surgical stimulus. There was no significant difference between the groups in PAOP and CVP. One patient in the metoprolol group had marked bradycardia (minimum heart rate 26 beat min-1) after neostigmine and atropine; otherwise metoprolol pretreatment was tolerated well.

Adult↗
PubMed1986

A new photographic-based system for the measurement of contrast sensitivity.

A new photographic-based system has been developed for the measurement of contrast sensitivity in human vision. The system has several advantages over other photographic methods and is relatively easy and inexpensive to produce. This paper describes the design of the new system and the methods used in the production of the photographic prints. Preliminary tests show that full contrast sensitivity curves can be obtained with a small number of photographic prints and that these curves are very similar to those obtained using a carefully calibrated electronic pattern generator.

Form Perception↗
PubMed1986

Membranous glomerulonephritis.

In a clinicopathological survey of idiopathic membranous glomerulonephritis (MGN) in 85 patients the predominance of the condition among men could be at least partly explained by an increased risk of exposure to organic solvents and heavy metals in the course of work. This may have implications for the advice given to these patients after MGN has been diagnosed. The selectivity of proteinuria could predict the likely outcome of the disease.

Adolescent↗
PubMed1986

Analysis of a prospectively randomized comparison of doxorubicin versus 5-fluorouracil, doxorubicin, and BCNU in advanced gastric cancer: implications for future studies.

A multi-institutional cooperative study of patients with locally advanced, recurrent, or metastatic gastric adenocarcinoma who had not previously received chemotherapy was conducted, prospectively randomizing patients to receive either doxorubicin or the three-drug combination, 5-fluorouracil (5-FU), doxorubicin (Adriamycin; Adria Laboratories, Columbus, Ohio), and BCNU (FAB). The 187 evaluable patients were initially stratified according to the presence of measurable or evaluable disease and performance status. There was a significantly higher response rate observed for FAB (40%) compared with doxorubicin (13%) among the 145 measurable-disease patients. Duration of response and survival were significantly longer for FAB in the measurable-disease group, but for the total patient population an early advantage for FAB in time to disease progression and survival was lost with continued follow-up. Median survival was 33 weeks for patients receiving FAB and 19 weeks for those receiving doxorubicin. Significant pretreatment factors adversely affecting survival included poor performance status, weight loss of greater than 10%, and more than two sites of metastases. Toxicity was not severe in either treatment arm, and only thrombocytopenia occurred significantly more often with FAB. It is contended that in the treatment of advanced gastric cancer, chemotherapy only exerts a relatively short-term and modest beneficial effect, most apparent in patients with intermediate tumor bulk. 5-FU remains the most active single agent, and combination chemotherapy has not yet proven its overall worth. Further studies are indicated comparing the most active combinations with 5-FU using optimal doses and schedules, and consideration must be given to the incorporation of no-treatment controls.

Adenocarcinoma↗
PubMed1985

Proliferative glomerulonephritis and exposure to organic solvents.

Exposure to organic solvents was compared by interview and questionnaire in 50 patients with biopsy-proven proliferative glomerulonephritis in whom there was no evidence of systemic disease or preceding infection with that of 100 control subjects matched for age, sex and social class. The interview was conducted by a lay person who did not know whether the interviewee was a patient with glomerulonephritis or a control subject. The exposure scores derived from the results of the questionnaires were significantly greater in the patients with glomerulonephritis than the control subjects (13,186 +/- 3,716 vs. 3,030 +/- 1,152, p less than 0.01). The degree of exposure was higher in those patients with the more severe diffuse endocapillary proliferative glomerulonephritis than in those with mesangial proliferative glomerulonephritis. In the glomerulonephritis patients solvent exposure was mainly occupational in origin and involved fuels, paints and degreasing agents in most cases. This occupational exposure was significantly greater than in the control subjects (13,061 +/- 3,858 vs. 2,878 +/- 1,146, p less than 0.01). It is suggested that exposure to organic solvents may participate in the pathogenesis of non-systemic proliferative glomerulonephritis.

Biopsy↗
PubMed1985

Membranous nephropathy in a patient with nail-patella syndrome nephropathy.

Membranous nephropathy is described in a patient with nail-patella syndrome who also had the characteristic changes of nail-patella syndrome nephropathy on electron microscopy. This combination has not previously been reported. Nail-patella syndrome nephropathy is reviewed in relation to other glomerular lesions which have been reported.

Adult↗
PubMed1979

Metabolic changes in blood and skeletal muscle in reconstructive aortic surgery.

The declamping shock has been attributed to reactive hyperemia with pooling of blood in the legs, metabolic acidosis following lactate accumulation in the ischemic leg muscles and hyperkalemia. We have studied eight patients undergoing arterial reconstruction with temporary aortic occlusion, in six cases because of obstructive arteriosclerotic disease and in two cases for aortic aneurysm. Muscle biopsies from the lateral vastus muscle as well as blood samples from the iliac vein, the superior caval vein and the radial artery were taken before clamping of the aorta, just before declamping, and 20 minutes after restitution of leg blood flow. ATP, ADP, AMP, phosphocreatine (PCr), creatine (Cr), glycogen, glucose, lactate, pyruvate and NH4+ from the immediately frozen muscle biopsies as well as lactate and pyruvate in the iliac vein and central venous blood were determined with an enzymatic, fluorometric technique. Only one patient reacted with a temporary hypotension at declamping. Arterial pH was unaffected during the operation, and no hyperkalemia was noted. During clamping of the aorta an increased lactate/pyruvate ratio in muscle indicated tissue hypoxia. Energy charge (EC) was, however, unchanged and the adenylate pool was maintained possibly due to a decrease in PCr. In spite of the restitution of blood flow after declamping of the aorta, no normalization of the metabolic state was seen, not even 20 minutes after the release of the clamp. EC was still unchanged but a significant decrease of both the adenylate and creatine pools was seen. These findings might indicate a damage of the mitochondria and the cellular membranes in skeletal muscle after temporary arterial occlusion.

Adult↗
PubMed1979

Artificial ventilation in children during anaesthesia using a tidal volume ventilator.

Standards for artificial pulmonary ventilation at ventilatory frequencies of 15 and 20 cycles per min, (PETCO2 4 +/- 0.5 kPa), were defined in 16 children with healthy lungs and body weights between 2.6 and 22.6 kg. A tidal volume ventilator and balanced anaesthesia were used during abdominal surgery. At f = 20 cycles/min an approximately direct proportionality existed between tidal volume and body weight (VTpat = 12.3 . kg b.w.--2.1, r = 0.99). The mean value VTpat per kg b.w. was 12.1 +/- 1.4 ml/kg. At f = 15 cycles/min, a linear relationship between tidal volume and kg b.w. was recorded (VTpat = 14.6 . kg b.w. + 16, r = 0.97). The mean value VTpat per kg b.w. was 15.9 +/- 1.5 ml/kg. A significant decrease in total compliance was recorded during the initial part of the surgical procedure. A rectilinear relationship existed between total compliance and kg b.w. (CTOT = 11.2 . kg b.w.--12.5, r = 0.95). The mean value CTOT per kg b.w. was 9.7 +/- 0.54 ml/kPa/kg at f = 20. The endotracheal peak pressure maintained a fairly constant pressure level independent of the initial pressure within the ventilator, the tidal volume and the body weight, a phenomenon explained by the hypothesis that the proportional increase in total lung volume and functional residual capacity in the older children compensated for the higher pressures.

Abdomen↗
PubMed1978

Partial lipodystrophy with nephrotic syndrome.

A patient with nephrotic syndrome in association with partial lipodystrophy is reported. The features of partial lipodystrophy are well recognized and the renal lesion is a mesangiocapillary glomerulo-nephritis of a dense deposit type with an associated depression of C3. This type of kidney involvement is becoming increasingly recognized as common in the syndrome of partial lipodystrophy.

Adolescent↗