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Biomedical subjects

N Hillman

Publications and source records attributed to N Hillman.

At least 19 recordsLinked to original sources
PubMed2004

What is the relative contribution of blood glucose levels at different time points of the day to HbA1c in Type 1 diabetes?

AIMS: To evaluate the relative contribution of blood glucose levels at different time points of the day to HbA(1c) in Type 1 diabetes. METHODS: Consecutive home blood glucose records (n = 146) from 71 Type 1 diabetic patients who were on an intensive diabetes therapy programme were examined. Each home blood glucose record included six daily blood glucose profiles over 2 months. The relationship between glycaemic values at each time point and HbA(1c) measured at the end of each record period was analysed. RESULTS: Significant linear correlations were found between HbA(1c) and glycaemia at each time point of the day (ranged from 0.413 to 0.593), the strongest being with predinner glycaemia (r = 0.593; P = 0.000). Total daily glycaemia, mean preprandial and mean postprandial glycaemia were also significant and linearly correlated with HbA(1c) (r = 0.701; r = 0.686; r = 0.620, respectively; P < 0.0001). Multiple linear regression analysis showed that predinner, prebreakfast and post-breakfast glycaemia correlated significantly and independently with HbA(1c). The model accounted for 47.8% of the variance in HbA(1c). CONCLUSIONS: Our study shows that among individual time points, prebreakfast and predinner are those with more influence on HbA(1c) in Type 1 diabetes and, to a lesser extent, post breakfast. It also confirms that preprandial glycaemia better predicts overall glycaemic control in Type 1 diabetes than postprandial glycaemia.

Blood Glucose↗
PubMed2002

Resection of Kommerell's diverticulum and left subclavian artery transfer for recurrent symptoms after vascular ring division.

OBJECTIVES: A Kommerell's diverticulum in patients with a right aortic arch may become aneurysmal and be an independent cause of tracheoesophageal compression, even after ligation and division of a left ligamentum. We review the indications for and results of Kommerell's diverticulum resection and left subclavian artery transfer in children with a right aortic arch who previously underwent vascular ring (ligamentum) division. METHODS: From 1998 through 2001, eight children have been referred with recurrent respiratory symptoms (n=8) and/or recurrent dysphagia (n=4) after vascular ring division. Each child had a right aortic arch with a left ligamentum and had undergone division of the ligamentum elsewhere. All had a Kommerell's diverticulum that was not addressed at the initial operation. All patients had a repeat left thoracotomy with resection of the diverticulum. Five patients had division and reimplantation of the left subclavian artery into the left carotid artery to relieve the sling-like effect of the retroesophageal left subclavian artery on the right aortic arch. One other patient had primary Kommerell's diverticulum resection and transfer of the left subclavian artery to the left carotid artery. RESULTS: The mean age at the initial operation was 1.7+/-0.9 years, and the mean age at reoperation was 8.0+/-3.7 years. In all patients postoperative bronchoscopy confirmed relief of the tracheal compression. There were no complications related to the subclavian artery transfer. Two patients developed postoperative chylothorax, one requiring thoracic duct ligation. The median hospital stay was 5 days. All patients had dramatic resolution of their preoperative symptoms. CONCLUSIONS: Kommerell's diverticulum is an important anatomic structure that can cause recurrent symptoms in patients with a right aortic arch after ligamentum division. In selected patients, reoperation with resection of the Kommerell's diverticulum and transfer of a retroesophageal left subclavian artery results in relief of symptoms. This technique has become our procedure of choice as a primary operation for children with a right aortic arch and a significant Kommerell's diverticulum.

Adolescent↗
PubMed2001

Increased numbers of caveolae in retinal endothelium and pericytes in hypertensive diabetic rats.

PURPOSE: Long-term clinical studies have now shown that tight control of blood pressure in type 2 diabetes reduces the risk of diabetes-related death and common diabetic complications, including diabetic retinopathy. However, the mechanisms by which hypertension enhances diabetic microvascular disease, especially diabetic retinopathy, are poorly understood. We developed an experimental model of hypertension in diabetic rats and studied the early ultrastructural changes in retinal capillaries under these conditions. METHODS: Hypertension was induced in diabetic BioBreeding (BB) rats by unilateral nephrectomy, weekly subcutaneous mineralocorticoid and 0.9% oral saline. Serial blood pressures and ultrastructural features of retinal capillaries were recorded in four groups: normotensive Wistar rats, normotensive diabetic rats, hypertensive Wistar rats and hypertensive diabetic rats. RESULTS: A significant and sustained increase in systolic blood pressure occurred in both groups of nephrectomised rats. There was a significant increase in the number of caveolae (i) in both pericytes and endothelial cells in animals with hypertension and diabetes together compared with all other groups and (ii) in pericytes in animals with diabetes alone. The number of direct contacts between pericytes and endothelial cells was reduced in diabetic and hypertensive diabetic animals. Hypertension and diabetes had an interactive effect in producing retinal capillary basement membrane thickening. CONCLUSIONS: In the BB rat hypertension and diabetes have an interactive effect in increasing the number of caveolae in both endothelial cells and pericytes. We speculate that this may be a reflection of changes in calcium and nitric oxide metabolism in these animals.

Animals↗
PubMed1999

Hepatobiliary dysfunction as the initial manifestation of disseminated cryptococcosis.

A case of hepatobiliary dysfunction as the initial manifestation of disseminated cryptococcosis is described. The patient was admitted with symptoms of hepatitis with cholestatic jaundice. Antibody tests for hepatitis B and C and human immunodeficiency virus were negative. The patient continued to deteriorate clinically. Eventually, the patient succumbed to hepatic failure. Autopsy disclosed systemic cryptococcosis that caused extensive necrosis of the liver. In review of the literature, only nine cases of cryptococcal infection presenting as hepatitis, cholangitis, and cholecystitis as initial manifestation were reported. Four of these patients had been subjected to exploratory laparotomy for clinical suspicion of acute abdomen. One patient developed cirrhosis as a result of cryptococcal hepatitis. Two patients succumbed to hepatic failure. Cryptococcosis is known to occur commonly in immunocompromised patients, yet only two reported cases presenting as hepatitis were associated with immunocompromised status.

Aged↗
PubMed1998

Decreased heart-period variability in patients with panic disorder: a study of Holter ECG records.

This study investigated cardiac autonomic function in patients with panic disorder and normal controls using Holter ECG records. A decrease in ultra-low frequency power (< 0.0033 Hz) is known to be associated with an increased risk for cardiovascular mortality in humans. Twenty-four-hour ECG was recorded in 29 patients with panic disorder and 23 normal controls using Holter records. Data for 20 h and also 20000 s of awake and 20000 s of sleep periods were analyzed using spectral analysis to quantify absolute and relative heart-period variability in ultra low (ULF: < 0.0033 Hz), very low (VLF: 0.0033-0.04 Hz), low (LF: 0.04-0.15 Hz) and high (HF: 0.15-0.5 Hz) frequency bands. The patients with panic disorder had significantly lower total and absolute ULF power, which was more pronounced during sleep. The patients also had significantly lower relative ULF power and significantly higher relative LF power during sleep. There was a significant increase of relative LF power from awake to sleep period only in the patient group. The decrease in total and ULF power may increase the risk of mortality and sudden arrhythmic death in patients with panic disorder if they experience a cardiac event. The higher relative LF power during sleep also suggests a possible higher sympathetic drive in the patients during sleep.

Adult↗
PubMed1998

Efficacy of octreotide in the regression of a metastatic carcinoid tumour despite negative imaging with In-111-pentetreotide (Octreoscan).

We present the case of a 52-year old patient diagnosed with carcinoid tumour of the rectum with liver metastases in which treatment with somatostatin analogues (octreotide) proved very effective in the disappearance of the symptomatology and dramatic efficacy in the regression of the tumour. Imaging by octreoscan was always negative. The role of octreotide in the treatment of carcinoid tumour and the usefulness of In-111-pentetreotide (octreoscan) in the localization and prediction of the response to treatment with octreotide is discussed. We conclude that the negative result of the scintigraphic image with octreoscan does not necessarily suppose the inefficacy of octreotide treatment. We believe that this may constitute an important issue since some patients may be denied octreotide treatment in the absence of a positive octreoscan result.

Antineoplastic Agents, Hormonal↗
PubMed1997

[Characterization of steroid 21-hydroxylase gene mutations in a oligosymptomatic form of congenital adrenal hyperplasia: family study].

BACKGROUND: 21-hydroxilase deficiency accounts for over 90% of all cases of congenital adrenal hyperplasia (CAH). There is a non-negligible incidence of both severe and nonclassical forms of this genetic disorder. Enzyme deficiency is due to mutations in the gene encoding adrenal 21-hydroxylase (named CYP 21B) and is inherited in an autosomical recesive way. Complete or partial impairment of enzyme activity has been correlated with the different clinical forms of the disease. PATIENTS AND METHODS: In the present paper CYP 21B gene analysis results obtained in a family with two kindred affected by a nonclassical form of the disease are shown. Clinical assessment of these two kindred showed a very mild form of the disease, whereas biochemical results suggested a late-onset partial 21-hydroxylase deficiency. Genotyping for deletions and 10 point mutations in the CYP 21B gene was performed by Southern blot analysis and polymerase chain reaction (PCR) allele-specific oligonucleotide (ASO) hybridation technique. RESULTS: Molecular genetic analysis performed in the two affected patients and two further relatives allowed us to detect the presence of different mutations in the two alleles of the CYP 21B gene. One of these mutations was severe (655G) and came from maternal line, whereas the other was mild (Val281Leu) and originated in paternal line. CONCLUSION: Molecular genetic analysis allows the possibility of finding severe (and non-expected) mutations in patients with clinically mild and late-onset forms of the 21-hydroxylase deficiency.

Adolescent↗
PubMed1997

Diffuse histoplasmosis in a patient with sarcoidosis.

A case is presented of a woman with a long history of sarcoidosis who developed diffuse histoplasmosis. Although association between these two entities has been described before, there are only a few case reports of histoplasmosis among sarcoid patients. Diagnosis was finally established by bone marrow biopsy which saved the patient's life.

Adult↗
PubMed1997

Hürthle cell tumors.

OBJECTIVES: a) To provide a clinicopathological profile of Hürthle cell neoplasms (HCT) in our experience. b) To evaluate if there are any differences in the clinical or morphological features between three HCT categories: benign, malignant and indeterminate. c) To examine the role of the clinical and morphological features in predicting the behavior of these neoplasms. METHODS: We reviewed the clinical reports of all patients with a histological diagnosis of HCT at our Hospital between 1981 and 1996. The final study group consisted of 25 cases. The neoplasms were divided into three categories on the basis of presence and degree of capsular and vascular invasion, marked nuclear atypia, tumour necrosis and pattern of growth. A series of clinical parameters were evaluated. RESULTS: Of the 25 tumors, 52% were morphologically classified as benign, 8% as indeterminate and 40% as malignant. Follow-up ranged from 10 months to 14.8 years or until death (average 3.8 years). There were four local recurrences (20%), three in the malignant group (30%) and one in the benign group (7.6%) (p = 0.15). One patient presented metastases and died because of tumor during the follow-up. Apart from capsular and vascular invasion and some aspects of therapy, no significant differences were found in the clinical and histological parameters analyzed between the three histological groups or between the groups with or without recurrence. CONCLUSION: We did not find any clinical or morphological parameter which can predict recurrence among these tumors. Our study further establishes the controversial issues surrounding the biological behavior of Hürthle cell neoplasms.

Adenoma, Oxyphilic↗
PubMed1991

A method for obtaining a pure population of t6/t6 mouse embryos prior to developmental arrest.

Developmental delay, as the result of ovariectomy, causes mouse blastocyst embryos obtained from +/t6 inter se matings to separate into two distinct populations when placed into outgrowth medium. One population remains as free floating embryos for a significantly longer period of time than the other population. Based upon their phenotypic expression following attachment and outgrowth, the former population was considered to be composed entirely of t6/t6 embryos and the latter, to be composed of +/+ and +/t6 embryos (Nadijcka et al., '81). In the present study, two-dimensional gel electrophoresis identified the embryos which were delayed in attachment as t6/t6 embryos since they synthesize only p63/6.9a, a product of the Tcp-1a locus which is unique to t-haplotypes. The early attaching embryos, assumed to be +/+ and +/t6, synthesize both p63/6.9a and b. The p63/6.9b protein is coded for by Tcp-1b on the wild-type homologous chromosome. Control +/+ blastocyst embryos synthesize only p63/6.9b. The data show that t6/t6 embryos can be identified prior to their lethal period and, thus, subjected to comparative studies to determine the cause of their lethality. Developmental delay is the first method established to enable one to unambiguously identify t6/t6 embryos prior to developmental arrest.

Animals↗
PubMed1991

Glass-bead column separation of motile and nonmotile human spermatozoa.

Glass-bead columns were tested for their efficiency in concentrating motile human spermatozoa from frozen semen samples. The data show that glass-bead filtration concentrates the motile gametes in each sample and is significantly more efficient than the swim-up method for obtaining populations of motile spermatozoa. The data suggest that this method can be applied clinically to obtain motile spermatozoa from poor-quality semen for use in in vitro fertilization.

Cell Count↗
PubMed1991

The in vivo and in vitro transmission ratio distortion of one complete and two partial t haplotypes in mice.

The effects of different types of insemination (normal and delayed matings and in vitro fertilization) on the transmission ratio distortion (TRD) of three t haplotypes were determined. The tw73 haplotype which contains all of the loci known to affect TRD is transmitted at equivalent frequencies in normal matings and in in vitro fertilizations (0.84 and 0.85, respectively) but at a significantly lower frequency (0.62) in delayed matings. The distal partial th18 haplotype is transmitted at equivalent frequencies in all types of insemination (0.66 to 0.70) while the proximal partial tw18 haplotype is transmitted in Mendelian frequencies in normal matings and in in vitro inseminations but at a significantly lower frequency in delayed matings. The results are discussed with reference to the current genetic model for transmission ratio distortion.

Animals↗
PubMed1990

The extended survival of tw5/tw5 mouse embryo cells in vitro.

The tw5 haplotype is a recessive mutation which is lethal when homozygous in mouse embryos following implantation. This series of studies was undertaken to determine the effect of the tw5/tw5 genotype on embryos developing in vitro. Blastocyst embryos from +/tw5 inter se matings were compared with control blastocysts obtained from matings between T/+ and +/+ females and +/tw5 males for their abilities to continue development in vitro in two culture media. The data show that there are no significant differences between the percentages of experimental and control blastocyst embryos which attach and outgrow or which contain inner cell masses on any day of culture up to equivalent gestation day 21 in either media. These findings show that the life span of cells from tw5/tw5 embryos can be extended significantly by in vitro culture.

Animals↗
PubMed1989

The in vivo and in vitro transmission frequencies of the tw5-haplotype in mice.

The recessive tw5-haplotype, a complete haplotype, is transmitted by heterozygous male mice at very high frequencies (greater than 0.90) in normal matings. The present studies were undertaken to determine the effects of delayed matings and in vitro fertilizations on this phenotypic expression. Males carrying the tw5-haplotype (+/tw5) were first tested for their frequencies of transmission of the mutant 17th chromosome in both normal and delayed matings. Spermatozoa obtained from these same males were then used to fertilize eggs in vitro. The in vivo and in vitro transmission frequencies were found to be statistically equivalent in all types of inseminations. An in vitro fertilization time course study showed that the same percentages of eggs are fertilized by tw5-bearing spermatozoa when the gametes are coincubated for either 2 or 6 h. The data lead to the conclusion that the transmission frequency of the tw5-haplotype is not affected either by the length of time elapsing between insemination and fertilization or by the environment in which fertilization occurs.

Animals↗
PubMed1989

The transmission ratio distortion of the th2-haplotype in vivo and in vitro.

The th2-haplotype is transmitted at low frequencies (less than 0.30) by +/th2 males in normal matings. In the studies described here, the transmission frequency of the th2-haplotype from Rb7/th2 males was determined for normal and delayed matings and in vitro inseminations. The data show the transmission frequency from the two in vivo inseminations to be less than 0.30 and to be statistically equivalent. However, the in vitro transmission frequency (0.80) is significantly greater than either of the in vivo frequencies. The results show that the environment in which fertilization occurs affects the transmission frequency of this specific t-haplotype significantly.

Animals↗
PubMed1989

Acrosin activity in spermatozoa from sterile t6/tw32 and fertile control mice.

Spermatozoa from sterile t6/tw32 and control fertile +/+, T/tw32, T/t6 mice were compared for their abilities to hydrolyse protein matrices and for their levels of acrosin activity. The data show that the immature and mature gametes from both the experimental and control males hydrolyse protein matrices. The quantitative acrosin assays show, however, that the mature gametes from the intercomplement males have significantly less total acrosin activity than any of the control groups of gametes. These findings suggest that this reduced acrosin activity is an additional phenotypic expression of the intercomplement genotype which results in male sterility.

Acrosin↗
PubMed1989

Cutaneous T cell lymphoma with suppressor phenotype and function.

Cutaneous T cell lymphomas (CTCL) are typically malignancies of postthymic helper T cells which retain helper function when assayed in vitro. We have described a case clinically and morphologically consistent with CTCL, but in which the tumor cells unequivocally had a suppressor T cell phenotype and suppressor function. This case could be differentiated from other varieties of peripheral T cell lymphomas by multiple clinical and laboratory parameters. The increasingly routine use of immune phenotyping in the evaluation of malignant lymphomas will likely result in the identification of additional cases of this entity, which should be studied to assess its clinical and prognostic relationship to the more common helper cell CTCL.

Humans↗