Biomedical subjects

M Horowitz

Publications and source records attributed to M Horowitz.

At least 145 records · Page 8Linked to original sources

PubMed1998

Calcium supplementation suppresses bone resorption in early postmenopausal women.

In order to establish whether calcium supplementation suppresses bone resorption in early postmenopausal women and whether any response is related to calcium absorption status, we studied 22 healthy women (median age 52 years) all within 5 years of the menopause. Urine was collected between 9.00 p.m. and 9.00 a.m., and 9.00 a.m. and 9.00 p.m., (2 days) and a fasting blood and spot urine sample was obtained at 9 a.m. On the first day, 5 microCi of 45Ca in 250 ml water with 20 mg calcium carrier as the chloride was given at 9.00 a.m. and a further blood sample was obtained at 10.00 a.m. to measure calcium absorption. A 1 g calcium load was given at 9.00 p.m., immediately before the second 24-hour urine collection. There was a rise in plasma ionized calcium (1.18 +/- 0.010 mmol/liter versus 1. 21 +/- 0.011 mmol/liter, P < 0.01) and a fall in plasma PTH (4.2 +/- 0.34 pmol/liter versus 3.5 +/- 0.31 pmol/liter, P < 0.01) from baseline after the calcium load, and a trend for the magnitude of the change in PTH to be inversely related to calcium absorption (r = -0.33, P = 0.13). In the fasting spot urine samples, there were falls in hydroxyproline (OHPr/Cr; 14.6 +/- 0.71 versus 12.6 +/- 0.83, P < 0.001), pyridinoline (Pyr/Cr; 75 +/- 2.8 versus 70 +/- 3.5, P < 0.05), and deoxypyridinoline (Dpd/Cr; 22.7 +/- 1.2 versus 19.5 +/- 1. 1, P < 0.005) after the calcium load. The calcium load suppressed urinary Dpd/Cr between 9.00 p.m. and 9.00 a.m. (P < 0.005), but not between 9.00 a.m. and 9.00 p.m. We conclude that acute administration of a 1 g calcium load suppresses bone resorption in early postmenopausal women, probably by decreasing PTH secretion.

Amino Acids↗

PubMed1998

Sagittal sinus thrombosis following minor head injury treated with continuous urokinase infusion.

BACKGROUND: Cerebral dural sinus thrombosis is a rare clinical entity. Symptoms may be vague, and left untreated thrombus progression may be fatal because of venous congestion and infarction. METHODS: We report a case of post-traumatic dural sinus thrombosis treated with selective transfemoral, transvenous catheterization and infusion of urokinase. RESULTS: Urokinase infusion into the dural venous sinuses using a microcatheter introduced from the femoral vein was successfully carried out, and patency of the venous sinuses was reestablished. CONCLUSION: Venous sinus thrombosis can be an overlooked sequel to head injury. If the diagnosis is entertained, prompt performance of appropriate imaging studies should be instituted so that therapy can be initiated. The use of selective sinus catheterization using microcatheter techniques with instillation of urokinase is an excellent mode of therapy that should be considered in any patient with symptomatic occlusion.

Adult↗

PubMed1998

Subarachnoid hemorrhage during arteriovenous malformation embolization as a result of vessel wall "sandblasting".

OBJECTIVE: Preoperative selective particulate embolization of arteriovenous malformations can make subsequent surgical resection of such lesions safer for the patient and easier for the surgeon. Nevertheless, embolization carries intrinsic risks, which include subarachnoid hemorrhage. We report two cases of subarachnoid hemorrhage during particulate embolization that we think was attributable to catheter positioning near a vessel curve and subsequent denudation of the vessel wall to the degree that hemorrhage was induced.

Adult↗

PubMed1998

Biofeedback therapy for children with dysfunctional voiding.

OBJECTIVES: Biofeedback therapy has been recognized as a treatment option for children with classic dysfunctional voiding (DV) where there is inadequate pelvic floor relaxation during voiding. However, there are few articles that discuss methodology and limited sites where it is available. In the hope of making biofeedback a more practical and accessible option, we report our indications, easy to duplicate methodology, and results. METHODS: Twenty-one consecutive children diagnosed with DV refractory to standard therapy were enrolled in our biofeedback program. Therapy consisted of extensive age-appropriate explanations of DV and demonstrations of normal and abnormal voiding patterns. Cyclic uroflow studies with pelvic floor electromyography are performed, which the child monitors on analog chart and audio recorders. The child returns weekly until consistent relaxation of the pelvic floor during voiding is demonstrated. Timing between sessions is then increased to monitor progress and retention of concepts previously taught. RESULTS: An excellent clinical response was one in which there was consistent relaxation of the pelvic floor throughout voiding, normal flow pattern, and no residual urine volume (urodynamic response), coupled with profound resolution of voiding symptoms. Seventeen of 21 (81%) had an excellent response, 3 (14%) had a fair response, and 1 (5%) was too inconsistent to rate. The average number of sessions to achieve a consistent urodynamic response was 3.7 (range 2 to 14) and full clinical response somewhat longer. Average follow-up since beginning therapy has been 34 months (range 14 to 51). CONCLUSIONS: Biofeedback therapy is an effective method for treating DV with poor pelvic floor relaxation. Although initially labor intensive, it yields sustained positive results in most patients in a short time.

Adolescent↗

PubMed1998

True hermaphrodite.

Explore the source record for details and available documents.

Disorders of Sex Development↗

PubMed1998

Relation between gastric emptying of glucose and plasma concentrations of glucagon-like peptide-1.

Glucagon-like peptide-1 (GLP-1) may play a role in regulating gastric emptying. The aim of this study was to determine the relationship between gastric emptying of glucose and plasma concentrations of GLP-1. Gastric emptying of 75 g of glucose dissolved in 350 ml of water was measured by the use of scintigraphy in 12 normal volunteers. Venous blood samples for measurement of GLP-1 were obtained immediately before and for 180 min after ingestion of glucose. Plasma GLP-1 rose rapidly from a baseline of 8.5 +/- 1.2 pmol/l to 14.3 +/- 1.3 pmol/l at 10 min (p = 0.024), with a peak of 19.2 +/- 3.0 pmol/l at 30 min (p = 0.0006) after the glucose drink. The rate of gastric emptying was inversely related to the early rise in GLP-1, e.g., the 50% emptying time was related to the change in GLP-1 from baseline at 10 min (r = 0.57; p < 0.05). We conclude that there is an inverse relationship between gastric emptying of glucose and plasma GLP-1. This observation is consistent with the concept that GLP-1 is a determinant of, rather than determined by, the rate of gastric emptying.

Adult↗

PubMed1998

T cell-depleted allogeneic bone marrow transplantation for high-risk non-Hodgkin's lymphoma: clinical and molecular follow-up.

The use of allogeneic BMT in patients with relapsed non-Hodgkin lymphoma (NHL) offers the advantage of tumor-free bone marrow and possibly a 'graft-versus-lymphoma effect' which may decrease the risk of recurrence. However, allogeneic BMT also poses an increased risk of death due to graft-versus-host disease (GVHD) which can be ameliorated by T cell depletion. We performed a retrospective review of 37 patients who underwent T cell-depleted allogeneic BMT for aggressive and indolent NHL between 1988 and 1996. Polymerase chain reaction (PCR) was used to identify indolent NHL patients with the BCL2/IgH translocation which served as a marker of residual disease. Sixteen of 37 patients (44%) are alive and progression-free with a median follow-up of 4.4 years (range 1-10.3). The incidence of grade 2-4 acute GVHD was 36% and extensive chronic GVHD developed in 12%. Patients with aggressive NHL have an overall PFS of 33% (12-54%); those with chemotherapy-resistant and sensitive disease have PFS of 17% (0-47%), and 40% (15-65%) respectively at 5 years. Patients with indolent histologies have overall PFS of 62% (37-86%); those with chemotherapy-resistant and sensitive disease have PFS of 55% (25-85%) and 80% (45-100%) respectively at 5 years. Eight patients with indolent disease had a BCL2/IgH translocation detectable by PCR. Five of these eight patients remain alive and progression free at a median of 6.5 years after BMT (range 2.1-7.4 years), four of whom remain PCR positive from 1.7 to 2.9 years after transplantation. We conclude that T cell-depleted allogeneic BMT poses a low risk for death due to GVHD, and should be considered for patients with relapsed and refractory indolent NHL.

Adolescent↗

PubMed1998

Rate of gastric emptying is a determinant of postprandial hypotension in non-insulin-dependent diabetes mellitus.

1. Postprandial hypotension is now recognized as an important clinical problem, particularly in the elderly and in patients with autonomic dysfunction. The mechanisms responsible are poorly understood; however, impaired regulation of splanchnic blood flow and the release of gastrointestinal hormones appear to be important. The effect of gastric emptying on the magnitude of the postprandial fall in blood pressure has not been evaluated. 2. The aim of this study was to determine whether there is a relationship between changes in blood pressure and the rate of gastric emptying after ingestion of 75 g of glucose in patients with non-insulin-dependent diabetes mellitus (NIDDM) and both young and older normal subjects. Sixteen patients with recently diagnosed NIDDM, median age 57 (39-79) years, 10 'young' subjects with a median age of 23 (19-26) years and nine 'older' subjects, median age 48 (40-68) years, were measured simultaneously for gastric emptying of 75 g of glucose in 350 ml of water blood pressure and blood glucose concentrations, commencing at approximately 10.00 hours after an overnight fast. Measurements of blood pressure were made in the sitting position immediately before glucose ingestion and at 15 min intervals up to 180 min. 3. Gastric emptying of glucose was not significantly different between the three groups [50% emptying time (T50): 95 +/- 7.3 min in patients with NIDDM compared with 120 +/- 13.2 min in the 'young' group and 97 +/- 8.1 min in the 'older' group]. There was a significant fall in mean blood pressure after the glucose load in the patients with NIDDM (P < 0.0001) and the 'older' normal subjects (P < 0.05), but not the 'young' normal subjects. Postprandial hypotension (fall in systolic blood pressure > or = 20 mmHg) was evident in seven (44%) patients with NIDDM and three (33%) 'older' normal subjects. The area under the change in mean blood pressure curve was related significantly to the gastric emptying T50 (r = 0.67, P < 0.005) in the patients with NIDDM, but not in either control group. 4. In conclusion, in patients with recently diagnosed NIDDM the fall in blood pressure after an oral glucose load is (i) greater than in both young and older normal subjects and (ii) related to the rate of gastric emptying.

Adult↗

PubMed1998

Intestinal calcium absorption in men with spinal osteoporosis.

OBJECTIVE: To investigate the role of serum 1,25-dihydroxyvitamin D (1,25D) in the decreased calcium absorption found in men with osteoporosis. DESIGN: Prospective study of patients referred to a university teaching hospital clinic for investigation of possible osteoporosis. PATIENTS: Male patients referred for investigation for osteoporosis, from 1981 to 1995, because of specific risk factors or radiological suspicion of osteoporosis. Men with vertebral compression fractures were compared with those without. MEASUREMENTS: Height and weight, radiocalcium absorption, serum 1,25D and fasting urinary calcium and hydroxyproline excretion. RESULTS: The men with vertebral fractures had higher fasting urinary hydroxyproline excretion (P = 0.003) and lower calcium absorption (P = 0.002) than the men without. Calcium absorption was positively related to 1,25D in both groups but the estimated calcium absorption at zero 1,25D was lower in the osteoporotic than the normal group. 1,25D was lower in the osteoporotic group than in the normal group. However this difference could only explain about half of the difference in calcium absorption between the groups. CONCLUSIONS: Calcium absorption is low in men with osteoporosis. About half of the deficit is due to low serum 1,25-dihydroxy vitamin D levels but there appears, in addition, to be some intestinal resistance to its effect on calcium absorption.

Adult↗

PubMed1998

A novel portable perfused manometric system for recording of small intestinal motility.

The development of solid-state catheters with miniature pressure transducers and portable dataloggers with a large memory capacity has allowed recording of gastrointestinal motility in ambulant subjects. Developments in silicone rubber extrusion technology made it possible to build a perfused manometric system, using a perfused manometric assembly requiring a low volume of perfusate. In the present study the feasibility of recording and automated analysis of small intestinal motility using a perfused multiple lumen manometric system was evaluated in seven healthy volunteers. Pressures were recorded from 12 sideholes arranged in four clusters spaced at 10-cm intervals from the catheter tip. Each channel was perfused at 0.15 mL min-1 with degassed water by a portable, low-compliance, perfusion pump. The 12 sidehole recording channels were connected to external transducers mounted on a belt. Pressure data were stored in two dataloggers. Motility was recorded in the sitting (30 min), and supine (30 min) position, during walking (30 min) and postprandially (90 min). Using purpose-built software baseline variations were corrected for and manometric variables (number of pressure waves, mean amplitude and motility index) calculated. Bench testing of the manometric assembly showed a median baseline pressure offset of 4.2 kPa (range 3.7-10.1) and upon occlusion a rise rate of 27.8 kPa sec-1 (range 19.7-30.8). Changes in body position affected baseline pressures so that compared to the supine position changes in baseline pressure varied between 1.5 +/- 0.7 kPa and 1.9 +/- 0.6 kPa during sitting (P < 0.02), and between 1.7 +/- 0.7 kPa and 1.5 +/- 0.9 kPa during walking (P < 0.03). Manometric recordings obtained during the fasting period showed an increase in small intestinal motor activity during walking. In the postprandial period no differences in motility variables were observed within one cluster and in time. Recording of small intestinal motility with a multiple-channel silicone rubber manometric assembly with a portable perfusion system is a feasible technique which is relatively inexpensive. Computer-assisted data processing allows for adequate elimination of artefacts and automated numerical analysis.

Adult↗

PubMed1998

Primary anal melanoma associated with melanosis of the upper gastrointestinal tract.

A 49-year old severely ill man, with no digestive complaints, was admitted to our hospital. Abdominal ultrasound was suggestive of hepatic metastases. Endoscopy revealed multiple, flat and polypoid, pigmented lesions in the esophagus, stomach and duodenum. Biopsy showed only melanotic pigment, without malignant cells. A bone marrow biopsy confirmed the diagnosis of metastatic melanoma. A flexible rectosigmoidoscopy revealed a dark polypoid lesion. Histological analysis confirmed the diagnosis of anal melanoma. These findings demonstrate that melanosis can occur concomitantly with anal melanoma and in different segments of the upper gastrointestinal tract.

Anus Neoplasms↗

PubMed1998

Interaction of insulin, glucagon-like peptide 1, gastric inhibitory polypeptide, and appetite in response to intraduodenal carbohydrate.

The relation between gastrointestinal incretin hormones in the control of insulin release and short-term satiety by intestinal carbohydrate was investigated in 8 fasted, healthy male volunteers. Insulin, gastric inhibitory polypeptide (GIP), glucagon-like peptide 1 (GLP-1), and appetite ratings were measured during, and food intake was measured after, intraduodenal infusions of glucose or saline. Studies were conducted under hyperinsulinemic and euglycemic conditions. Raising plasma insulin with intravenous insulin infusion to concentrations slightly above usual postprandial concentrations (356.4 +/- 4.8 pmol/L) had no effect on GIP, GLP-1, or appetite ratings before the intraduodenal infusions began. Intraduodenal glucose infusion resulted in a further increase in plasma insulin to a peak of 779.4 +/- 114.0 pmol/L, caused an early increase in plasma GIP and a later increase in GLP-1 concentrations (P < 0.01), suppressed appetite (P < 0.05), and reduced energy intake (P < 0.01) compared with intraduodenal infusion of saline. There was a close association between the increase in GLP-1 and decrease in appetite. Infusion of octreotide to suppress the release of gastrointestinal hormones prevented the rise in insulin, GIP, and GLP-1 induced by intraduodenal glucose infusion and reversed the suppression of appetite and reduction in energy intake. These results suggest that 1) when infused to result in plasma concentrations slightly above usual postprandial concentrations, insulin does not inhibit its own release and 2) the effects of intraduodenal glucose on appetite may be mediated through the release of GLP-1 and not insulin.

Adult↗

PubMed1998

The Koyanagi-Nonomura 1-stage bucket repair of severe hypospadias with and without penoscrotal transposition.

PURPOSE: We report our experience with 1-stage Koyanagi-Nonomura hypospadias repair, which may be performed even when penoscrotal transposition is present. Repair involves bilateral parameatal skin flaps based on the meatus and urethral plate. MATERIALS AND METHODS: A total of 14 boys 10 to 20 months old underwent 1-stage Koyanagi-Nonomura repair for severe hypospadias. The meatus was proximal to the penoscrotal junction in all patients, and in 8 penoscrotal transposition was corrected during the same operation. RESULTS: In 7 of the 14 boys 1 or more fistulas developed that were subsequently repaired. In all cases the fistula was on the proximal shaft and/or penoscrotal junction. In no case was there stenosis or breakdown of the distal neourethra. CONCLUSIONS: The Koyanagi-Nonomura 1-stage repair provides excellent cosmetic results in severe hypospadias while preserving the available urethral plate tissue. It is particularly suitable when there is associated penoscrotal transposition. Most if not all 1-stage repairs are inappropriate in patients with severe hypospadias and penoscrotal transposition. In other repairs vascular supply to Byar's flaps and the neourethra may be compromised by mobilization of the anteriorly transposed scrotal tissue. We expect that the fistula rate will decrease with experience but now it is acceptable, considering the severity of hypospadias.

Humans↗

PubMed1998

Posteroinferior cerebellar artery aneurysms: surgical results for 38 patients.

OBJECTIVE: Posteroinferior cerebellar artery aneurysms have an incidence of approximately 0.49%. Reports in the literature are sparse concerning outcomes in this patient population. We report our results for 38 consecutive patients who were treated during the last 6.5 years. METHODS: All patients (n = 38) with posteroinferior cerebellar artery aneurysms that were surgically treated at Zale-Lipshy University Hospital between January 1990 and May 1997 were retrospectively reviewed. Data were collected and analyzed relating to demographics, condition at presentation, lesion characteristics, associated medical problems, postsurgical complications, and outcome. RESULTS: Sixty-six percent of the patients (n = 25) experienced neurological sequelae, which included symptomatic vasospasm, hydrocephalus, dysarthria, paresis, diplopia, ataxia, and facial paralysis. Many, however, showed significant improvement during their hospitalization and during the course of the ensuing year. Seventy-four percent of the patients had a Glasgow Outcome Scale score of 1 or 2 at the time of discharge, 91% at 6 months after surgery, and 89% at 1 year after surgery. CONCLUSION: This review summarizes the presentations and outcomes of 38 consecutive surgical cases during a 6.5-year period and concludes that posteroinferior cerebellar artery aneurysms are not benign entities. The study does, however, also demonstrate that patients have significant recuperative potential after the treatment of these lesions.

Adult↗

PubMed1998

The effect of aging on bone mineral metabolism and bone mass in Native American women.

OBJECTIVE: To examine the effect of age on mineral metabolism and bone mineral density (BMD) of the hip and spine in Native American women. DESIGN: A cross-sectional study. SETTING: The Sac and Fox Nation in rural Oklahoma MEASUREMENTS: Serum measurements were made of 25 hydroxyvitamin D (25OHD), osteocalcin, and immunoreactive parathyroid hormone. Bone mineral density of the hip and spine was assessed by dual energy X-ray absorptiometry. PARTICIPANTS: A total of 77 Native American women aged 19 to 85 years. RESULTS: Serum 25 hydroxyvitamin D was related inversely to age (r = -0.32; P < .05) and was less than 15 ng/mL in 7% of the subjects. Serum osteocalcin was higher (P < .001) in postmenopausal than in premenopausal subjects. In postmenopausal subjects, serum osteocalcin was related to age (r = .59, P < .001). BMD was lower (P < .001) in postmenopausal than in premenopausal subjects. There was no evidence of bone loss before age 50 in either the femur or the spine. Age (r > or = -0.48, P < .001) and body mass index (BMI) (r > or = 0.41, P < .005) were independent determinants of both femoral and lumbar BMD. Serum 25OHD was a significant independent determinant of both lumbar (r = .26, P < .05) and femoral (r = .41, P < .01) BMD. Age, BMI, and serum 25OHD together accounted for 70% of the variance in BMD at these sites. The use of t scores indicated femoral bone density was higher (P < .05) in premenopausal Native American women, and lower (P < 0.05) in postmenopausal subjects, compared with white women. CONCLUSIONS: In Native American women, there is a reduction in bone density and a sustained increase in bone turnover postmenopausally. BMI and serum 25OHD are significant determinants of BMD. Peak BMD may be higher, and the postmenopausal rate of bone loss greater, than that in white women.

Adult↗

PubMed1998

Motor function of the proximal stomach and visceral perception in gastro-oesophageal reflux disease.

BACKGROUND: The abnormally high postprandial rate of transient lower oesophageal sphincter relaxations seen in patients with reflux disease may be related to altered proximal gastric motor function. Heightened visceral sensitivity may also contribute to reporting of symptoms in these patients. AIMS: To assess motor function of the proximal stomach and visceral perception in reflux disease with a barostat. METHODS: Fasting and postprandial proximal gastric motility, sensation, and symptoms were measured in nine patients with reflux disease and nine healthy subjects. Gastric emptying of solids and liquids was assessed in six of the patients on a different day (and compared to historical controls). RESULTS: Minimal distending pressure and gastric compliance were similar in the two groups, whereas the patients experienced fullness at lower pressures (p < 0.05) and discomfort at lower balloon volumes (p < 0.005) during isobaric and isovolumetric distensions respectively. Maximal gastric relaxation induced by the meal was similar in the two groups. Late after the meal, however, proximal gastric tone was lower (p < 0.01) and the score for fullness higher (p < 0.01) in the reflux patients, in whom the retention of both solids and liquids in the proximal stomach was greater (p < 0.05). CONCLUSIONS: Reflux disease is associated with delayed recovery of proximal gastric tone after a meal and increased visceral sensitivity. The former may contribute to the increased prevalence of reflux during transient lower oesophageal sphincter relaxations and the delay in emptying from the proximal stomach, whereas both may contribute to symptom reporting.

Adult↗

PubMed1998

Effect of glucose supplementation on appetite and the pyloric motor response to intraduodenal glucose and lipid.

The effects of different macronutrients on appetite and pyloric motility and the impact of short-term dietary glucose supplementation on these responses were evaluated. Ten males (aged 19-38 yr) received isocaloric (2.9 kcal/min) intraduodenal infusions of glucose and lipid while antropyloroduodenal motility and appetite were assessed by manometry and visual analog scales, respectively. Effects of each intraduodenal nutrient on appetite and motility were evaluated before and after 7 days of dietary supplementation with glucose (400 g daily). Initially, both nutrients caused a similar rise in pyloric tone, but intraduodenal lipid was a more potent stimulus of phasic pyloric motility (P = 0.05) and suppressed appetite more (P = 0.013) than intraduodenal glucose. After dietary glucose supplementation, the increase in pyloric tone during intraduodenal glucose was attenuated. Although intraduodenal lipid remained a more potent stimulant of phasic pyloric motility (P = 0.016), it no longer decreased appetite. We conclude that in healthy young males 1) intraduodenal infusion of lipid is a more potent stimulus of phasic pyloric motility and suppresses appetite more than intraduodenal glucose and 2) dietary glucose supplementation alters both the appetite suppressant effect of intraduodenal lipid and the pyloric motor response to intraduodenal glucose infusion.

Adult↗

PubMed1998

Physiological changes in blood glucose affect appetite and pyloric motility during intraduodenal lipid infusion.

We evaluated the effects of varying blood glucose concentration within the normal postprandial range and its interaction with small intestinal nutrients on antropyloric motility and appetite. Eight healthy males (19-40 yr) underwent paired studies, with a blood glucose level of 5 or 8 mmol/l. Manometry and visual analog scales were used to assess motility and appetite, during fasting and intraduodenal lipid infusion (1.5 kcal/min). In the fasting state, antral waves were suppressed at 8 mmol/l compared with 5 mmol/l (P = 0.018). However, pyloric motility was no different between the two blood glucose concentrations. Hunger was no different at 5 mmol/l compared with 8 mmol/l, but fullness was greater at 8 mmol/l (P = 0. 01). During intraduodenal lipid infusion, antral waves were suppressed (P < 0.035) and isolated pyloric pressure waves (IPPWs) were stimulated (P < 0.02) compared with during the fasting state, with no difference between blood glucose concentrations, although the temporal patterning of IPPWs varied between blood glucose concentrations. The amplitude of IPPWs was greater at 5 mmol/l compared with 8 mmol/l (P < 0.001), and hunger decreased at 8 mmol/l compared with 5 mmol/l (P = 0.02). We conclude that "physiological" hyperglycemia modifies gastric motor and sensory function and that synergy exists between blood glucose concentration and small intestinal nutrients in modulating gastric motility and appetite.

Adult↗