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Biomedical subjects

D Martin

Publications and source records attributed to D Martin.

At least 379 records · Page 21Linked to original sources
PubMed1996

Preliminary results of embolisation of nonsurgical intracranial aneurysms with GD coils: the 1st year of their use.

We report 28 patients with nonsurgical intracranial aneurysms referred by neurosurgeons for endovascular treatment using platinum detachable coils (GDC, Target Therapeutics, Fremont, Calif., USA). Because of unfavourable anatomical features or failed hyperselective catheterisation, 4 patients were not treated. In the other 24 patients (26 aneurysms) embolisation was successful. No manufacturing defect was detected in the coils used. Complete occlusion of the sac was obtained in 22 of the 26 aneurysms (85%) regardless of their size. The glasgow outcome score was good on discharge in 20 of the 24 patients (83%). The Karnovski score at 3 months after embolisation revealed that 20 patients (83%) lead a normal life, with minor neurological signs. Morbidity related directly to treatment occurred in 2 cases (8%): a superior hemianopia due to mass effect on the optic nerve from a carotid-ophthalmic aneurysm, and hemiparesis due to an embolus. Five transient deficits lasting hours to a few days were related to proven or suspected emboli. No death occurred. Anatomical, technical and clinical data are reported; the mean cost of materials (catheters and coils) per patient and aneurysm was FF 13,500. The mean hospitalisation time was 6.5 days in the neurosurgical department with 2.8 days of intensive care.

Adult↗
PubMed1996

Ethnographic perspectives on the enumertion of aboriginal people in remote Australia.

"This paper compares population counts and age distributions from the last two Australian Bureau of Statistics (ABS) enumerations of the Aboriginal population of Aurukun, Cape York Peninsula, with the results of detailed ethnographic surveys of the same population at similar points in time. This reveals substantially lower numbers for the ABS counts, particularly of young adults and children. Reasons for this discrepancy are sought in the ethnographic realities of remote indigenous communities and an alternative methodology for Aboriginal enumeration in remote regions is suggested."

Age Distribution↗
PubMed1996

[Combined pancreas/kidney transplantation as standard procedure in therapy of type I diabetic patients in renal failure].

Sinde the introduction of the bladder drainage technique, the number of pancreas transplants performed has now reached 1000/year worldwide. Most of these transplants have been performed in the United States. In contrast, the number of pancreas transplants performed in the Eurotransplant community has remained at a low level for several years. The results of a consecutive series of 20 simultaneous pancreas/kidney grafts (SPK) performed between June 1994 and October 1995 demonstrate that high graft function rates of 83.5% for pancreas and kidney grafts can be achieved. Therefore SPK can be recommended as a standard procedure for patients with insulin-dependent diabetes mellitus and end-stage renal disease in Germany, too.

Adult↗
PubMed1996

Trabecular bone cell proliferation ex vivo increases with donor age in the rat: it is correlated with the extent of bone loss and not with histomorphometric indices of bone formation.

Morphometric parameters of bone formation are markedly depressed in senescent, 21-month old rats and even in middle-aged, 12-month-old animals when compared with mature, 4-month old adults. However, osteoblast-like cells obtained from the metaphyseal trabeculae of the distal femur of 21-month-old female and male rats proliferate more rapidly in primary and secondary cultures than cells from 4-month-old donors. In females the increase in proliferation is significant for donor ages from 4 to 12 months and from 12 to 21 months. Ex vivo cell proliferation is inversely correlated with trabecular bone volume and bone surface in females and with bone surface in males. The relationships are being maintained in females (not tested in males) when cells are grown in serum-free medium. We interpret age and bone loss-dependent stimulated cell proliferation as the in vitro response to an in vivo signal to proliferate resulting from higher strains on less trabeculae. The absence of response in vivo could result from the local deficiency of factors brought back to the cells by the serum-enriched culture medium, or from proliferation inhibitors developing with age.

Aging↗
PubMed1996

Insertion/deletion polymorphism in the angiotensin-converting enzyme gene and risk of and prognosis after myocardial infarction.

OBJECTIVES: We sought to prospectively investigate whether genetic variation at the angiotensin-converting enzyme gene locus defined by an insertion (I)/deletion (D) polymorphism influences the risk of myocardial infarction or prognosis after infarction, or both. BACKGROUND: It has been suggested that the deletion allele of the angiotensin-converting enzyme gene, and specifically the DD genotype, may increase the risk of myocardial infarction, although previous studies have produced conflicting reports. No studies have yet examined the effect of I/D polymorphism on survival after infarction. METHODS: Angiotensin-converting enzyme genotypes in 684 patients with myocardial infarction recruited at the time of the acute event through coronary care units in two centers were compared with those of 537 control subjects recruited from the base populations. All patients were followed up to assess the impact of the angiotensin-converting enzyme genotype on prognosis. RESULTS: We found no difference (p = 0.89) in the genotype distribution between patients and control subjects (patients DD 31%, ID 47%, II 22%; control subjects DD 30%, ID 48%, II 22%). The odds ratio for myocardial infarction for DD compared with II/ID genotype adjusted for age, gender and center was 1.16 (95% confidence interval [CI] 0.82 to 1.65, p = 0.44). The study had 90% power to detect a 1.5-fold increase in risk of myocardial infarction associated with the DD genotype. For one center, data were available for other risk factors (hypertension, diabetes, angina, previous myocardial infarction, smoking, body mass index, total and high density lipoprotein cholesterol) in both patients and control subjects. In a stepwise logistic regression analysis the odds ratio for DD versus ID/II genotypes remained nonsignificant (1.44, 95% CI 0.84 to 2.46, p = 0.20) for these subjects. Over a median follow-up period of 15 months (range 3 to 22), 155 patients (22.7%) died. There was no difference in mortality between subjects with the DD genotype and those with ID/II genotypes. (21.8% vs. 23.1%, p = 0.25). Likewise, there was no difference in the distribution of survival times in the two groups (p = 0.62). The study had 70% power to detect a 1.5-fold increase in mortality during follow-up associated with the DD genotype. CONCLUSIONS: We conclude that in the groups studied, genetic variation at the angiotensin-converting enzyme gene locus defined by I/D polymorphism does not significantly influence either the risk of or the short- to medium-term prognosis after myocardial infarction.

Aged↗
PubMed1996

Evaluation of single isotope technetium 99M-sestamibi in localization efficiency for hyperparathyroidism.

BACKGROUND: Regardless of surgical effectiveness, ongoing activity in parathyroid localization in hyperparathyroidism (HPT) is an established enterprise. Sestamibi (MIBI), the most recent new modality, is being assessed in this regard. METHODS: Twenty mCI of 99 TC Sestamibi was administered intravenously in patients with prospective HPT. Images were assessed by pinhole and full-field gamma camera at 20 minutes and 2 hours. Dual-phase one isotope only was utilized. Patients were then studied for pathology and MIBI correlation. RESULTS: Sixty-three cases underwent MIBI scanning, 50, or 79%, of which were due to a single adenoma. Sensitivity showed in 41 of 50 adenomas and was 82% correct. Quadrant localization was 97%. Eleven patients showed hyperplasia with MIBI sensitivity of 82% on a case basis but only 31% for multiglandular disease. Overall MIBI sensitivity is 80%. One false-positive and one true-negative case were observed. All patients achieved eucalcemia. No operative morbidity of significance occurred. CONCLUSION: Scanning with 99M Sestamibi dual-phase technique is the preferred mode of parathyroid localization in current practice. It is of assistance in primary HPT, essential in recurrent HPT, and of use in ectopic gland detection. It can support surgical intervention in the marginal HPT patient. Scanning still requires bilateral exploration for complete assessment.

Adenoma↗
PubMed1996

Pharmacokinetics of lamivudine administered alone and with trimethoprim-sulfamethoxazole.

OBJECTIVE: To determine the effect of multiple dosing of combined sulfamethoxazole and trimethoprim on the single-dose pharmacokinetics of lamivudine. METHODS: Fourteen subjects with human immunodeficiency virus who had CD4+ cells > or = 200/mm3 received two single doses of 300 mg lamivudine, separated by 7 to 14 days, in a randomized two-day crossover study. Treatment consisted of lamivudine alone versus trimethoprim-sulfamethoxazole (160/180 mg) daily on days 1 through 4 followed by lamivudine plus trimethoprim-sulfamethoxazole on day 5. Blood and urine were collected over 24 to 32 hours to determine lamivudine, trimethoprim, sulfamethoxazole, and N-4-acetylsulfamethoxazole concentrations. RESULTS: Coadministration of a single dose of lamivudine and trimethoprim-sulfamethoxazole after daily dosing for 5 days altered the pharmacokinetics of lamivudine. A 43% increase in area under the concentration-time curve (AUC infinity) and a 35% decrease in renal clearance (CLR) were observed when lamivudine was coadministered with trimethoprim-sulfamethoxazole compared with lamivudine alone. The geometric least-squares trimethoprim-sulfamethoxazole were as follows: AUC infinity, 10,124 (9,432-10,866) and 14,448 (13,461-15,508) ng . hr/ml, respectively; CLR, 16.6 (14.1-19.4) and 10.8 (9.5-12.6) L/hr, respectively. Coadministration did not significantly alter the pharmacokinetics of trimethoprim or sulfamethoxazole. CONCLUSIONS: Coadministration of lamivudine with trimethoprim-sulfamethoxazole resulted in an increased AUC infinity and a decreased CLR of lamivudine. However, given the favorable safety profile of lamivudine, it is unlikely that this interaction will result in a significant increase in concentration-related toxicity at the doses studied.

Administration, Oral↗
PubMed1996

Laryngeal carcinoma in females.

Between 1950 and 1992, 96 women with squamous cell carcinoma of the larynx were diagnosed and treated in the Department of Otolaryngology and Oncology at Beilinson Medical Center, Israel, and Long Island College Hospital, Brooklyn, New York. Fifty-seven female patients (59%) had glottic carcinoma, 72% of them in stage I. Thirty-eight had supraglottic carcinoma, 68% of them in stages II and III. One patient had stage I subglottic carcinoma. Treatment varied between radiotherapy, surgery, or combined surgery with radiation and/or chemotherapy. The 5-year survival rate was 87%. Although most of the patients had glottic carcinoma in stage I, there was also a high percentage with supraglottic carcinoma, most in advanced stages and with metastases to other regions. The prognosis is not different from that in men. Smoking is an important factor in glottic carcinoma, but not as important as in males.

Carcinoma, Squamous Cell↗
PubMed1996

Evidence for multiple opioid receptors in the human posterior pituitary.

The distribution and quantification of opioid receptor types in post-mortem human pituitary cryostat sections was determined by quantitative in vitro receptor autoradiography. Highly specific radioligands were used for each opioid receptor type i.e. [125l]-FK-33-824 for mu-opioid sites, [125l][D.Ala2]-Deltorphin-l for delta-opioid sites and 3H-U69,593 for kappa-opioid sites. None of the five specimens tested exhibited any labeling in the anterior lobe of the pituitary for the three radioligands. As for the posterior pituitary, all 5 specimens contained both mu and kappa-opioid binding sites whereas none of them showed delta-binding sites. The presence of both mu- and kappa-opioid binding sites in the human posterior pituitary contrasts with previous findings in the rat where only kappa-sites have been found. The present study could contribute to understanding of the functional action of opioids in the human pituitary.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1996

Reduced brain N-acetyl-aspartate in frontal lobes suggests neuronal loss in patients with amyotrophic lateral sclerosis.

We performed proton magnetic resonance spectroscopy (1H-MRS) in three patients with amyotrophic lateral sclerosis (ALS) to evaluate the distribution and extent of cortical neuronal damage as demonstrated by decreased N-acetyl-aspartate (NAA) levels. We examined primary motor (precentral gyrus) and parietal neocortical (superior parietal gyrus) regions. ALS was defined with lower and upper motor neuron signs. Compared with matched healthy controls, ALS patients had a significant decrease in NAA levels in the primary motor cortex (p < 0.001) compared with parietal regions and homologous regions in healthy controls. Two clinical applications can be extracted: first, the upper motor neuron signs present in the ALS, come from a neuronal loss within the primary motor cortex and may explain the frontal syndrome associated with ALS. Second clinical applications of 1H-MRS could include identification of extent of upper motor neuron involvement, aiding diagnosis of syndromes presenting with an ALS-like syndrome.

Aged↗
PubMed1996

Poisson process approximation for sequence repeats, and sequencing by hybridization.

Sequencing by hybridization is a tool to determine a DNA sequence from the unordered list of all l-tuples contained in this sequence; typical numbers for l are l = 8, 10, 12. For theoretical purposes we assume that the multiset of all l-tuples is known. This multiset determines the DNA sequence uniquely if none of the so-called Ukkonen transformations are possible. These transformations require repeats of (l-1)-tuples in the sequence, with these repeats occurring in certain spatial patterns. We model DNA as an i.i.d. sequence. We first prove Poisson process approximations for the process of indicators of all leftmost long repeats allowing self-overlap and for the process of indicators of all left-most long repeats without self-overlap. Using the Chen-Stein method, we get bounds on the error of these approximations. As a corollary, we approximate the distribution of longest repeats. In the second step we analyze the spatial patterns of the repeats. Finally we combine these two steps to prove an approximation for the probability that a random sequence is uniquely recoverable from its list of l-tuples. For all our results we give some numerical examples including error bounds.

Algorithms↗
PubMed1996

Genetic analysis of thermolabile methylenetetrahydrofolate reductase as a risk factor for myocardial infarction.

Hyperhomocyst(e)inemia is associated with an increased risk of coronary artery disease and myocardial infarction. Both genetic and environmental factors influence the plasma level of homocysteine. One of the metabolic pathways for homocysteine involves the enzyme methylenetetrahydrofolate reductase (MTHFR), which regulates the conversion of homocysteine to methionine. A thermolabile variant of MTHFR is associated with reduced enzyme activity and increased plasma homocysteine levels. Recently, the cause of this variant of MTFHR has been identified as a single base change altering an alanine to a valine residue in the protein. Using a PCR-based assay to distinguish the normal and thermolabile variants of MTHFR in this study, we investigated whether the thermolabile variant is a genetic risk factor for myocardial infarction. In a study of 532 subjects (310 myocardial infarction patients and 222 population-based controls), we found no difference in either MTHFR genotype distribution (p = 0.57) or allele frequencies (p = 0.68) between cases and controls. The allele frequencies of the thermolabile variant were 0.34 and 0.35 in cases and controls, respectively. The age- and sex-stratified odds ratio for risk of myocardial infarction associated with homozygosity for the thermolabile variant was 0.85 (95% CI 0.50-1.50, p = 0.57) and that with carriage of the thermolabile allele was 1.06 (95% CI 0.73-1.52, p = 0.76). The odds ratios remained non-significant when restricted to young subjects (< 60 years) or males, and were not influenced by several other risk factors for myocardial infarction considered either singly or in combination. Interestingly, in both cases and controls, there was a trend toward a higher prevalence of hypertension in subjects carrying the normal allele, although as this is a post-hoc finding it needs to be interpreted with caution. The thermolabile variant of MTHFR is not a major risk factor for myocardial infarction and is unlikely to explain a significant proportion of the reported association of hyperhomocyst(e)inemia with coronary artery disease.

Adult↗
PubMed1996

Children's response to parental separation during operation desert storm.

OBJECTIVE: Commonly held attitudes concerning the effects of parental wartime deployment on children have usually been guided by stereotype, rather than scientific data. To determine the effects of Operation Desert Storm on military children and their parents, the authors compared children and families with and without a deployed soldier-parent prior to and during Operation Desert Storm. METHOD: Three hundred eighty-three children and the remaining caretaking parent completed self- and parent-report instruments concerning child and family functioning and life stressors. Children of deployed and nondeployed personnel were compared cross-sectionally, as well as longitudinally, using data collected prior to any knowledge of Operation Desert Storm. RESULTS: Children of deployed personnel experienced elevated self-reported symptom levels of depression, as did their parents. Likewise, families of deployed personnel reported significantly more intervening stressors, compared with children and families of nondeployed personnel. However, deployment per se rarely provoked pathological levels of symptoms in otherwise healthy children. CONCLUSIONS: Generally, the factors shaping differential outcomes among children of deployed personnel do not differ from the variables affecting outcomes of children of nondeployed parents. However, boys and younger children appear to be especially vulnerable to deployment effects, and increased monitoring of these children is warranted. Adequate treatment of children requires treatment of the effects of the deployment on other family members. For children showing more persistent or pervasive psychopathology, factors other than simple deployment should be considered.

Adjustment Disorders↗
PubMed1996

Glial cell line-derived neurotrophic factor: the lateral cerebral ventricle as a site of administration for stimulation of the substantia nigra dopamine system in rats.

The direct application of recombinant human glial cell line-derived neurotrophic factor (rhGDNF) to the deep structures of the nigrostriatum has been shown previously to augment dopamine function and inhibit loss of substantia nigra neurons in rodent models of Parkinson's disease. The present studies were designed to determine whether administration of rhGDNF into the lateral ventricle, a more clinically accessible intracranial target, is capable of augmenting dopamine function of the nigrostriatal pathway in normal rats. Single bolus intracerebroventricular (i.c.v) injections of rhGDNF increased locomotor activity and decreased food and water consumption and body weight gain in a dose-dependent manner. rhGDNF increased concentrations of dopamine and dopamine metabolites in the substantia nigra, ventral tegmental area and hypothalamus, but had no significant effects in the striatum. rhGDNF had no effect on striatal or substantia nigral serotonin (5-HT) and 5-hydroxyindoleacetic acid levels, but these levels were significantly increased in the ventral tegmental area and hypothalamus respectively. The augmentation of the dopamine and 5-HT systems was detected 2 weeks but not 3 days or 6 weeks after rhGDNF administration. After a repeat injection of i.c.v rhGDNF (6 weeks after the initial injection), substantia nigral dopamine, 5-HIAA and noradrenalin levels were increased. These results indicate that i.c. v administration of rhGDNF has an influence on adult rat dopamine neurons. This route of administration may be useful for stimulating dopamine neurons in Parkinson's disease.

Animals↗
PubMed1996

The relationship between capsid protein (VP2) sequence and pathogenicity of Aleutian mink disease parvovirus (ADV): a possible role for raccoons in the transmission of ADV infections.

Aleutian mink disease parvovirus (ADV) DNA was identified by PCR in samples from mink and raccoons on commercial ranches during an outbreak of Aleutian disease (AD). Comparison of DNA sequences of the hypervariable portion of VP2, the major capsid protein of ADV, indicated that both mink and raccoons were infected by a new isolate of ADV, designated ADV-TR. Because the capsid proteins of other parvoviruses play a prominent role in the determination of viral pathogenicity and host range, we decided to examine the relationship between the capsid protein sequences and pathogenicity of ADV. Comparison of the ADV-TR hypervariable region sequence with sequences of other isolates of ADV revealed that ADV-TR was 94 to 100% related to the nonpathogenic type 1 ADV-G at both the DNA and amino acid levels but less than 90% related to other pathogenic ADVs like the type 2 ADV-Utah, the type 3 ADV-ZK8, or ADV-Pullman. This finding indicated that a virus with a type 1 hypervariable region could be pathogenic. To perform a more comprehensive analysis, the complete VP2 sequence of ADV-TR was obtained and compared with that of the 647-amino-acid VP2 of ADV-G and the corresponding VP2 sequences of the pathogenic ADV-Utah, ADV-Pullman, and ADV-ZK8. Although the hypervariable region amino acid sequence of ADV-TR was identical to that of ADV-G, there were 12 amino acid differences between ADV-G and ADV-TR. Each of these differences was at a position where other pathogenic isolates also differed from ADV-G. Thus, although ADV-TR had the hypervariable sequence of the nonpathogenic type 1 ADV-G, the remainder of the VP2 sequence resembled sequences of other pathogenic ADVs. Under experimental conditions, ADV-TR and ADV-Utah were highly pathogenic and induced typical AD in trios of both Aleutian and non-Aleutian mink, whereas ADV-Pullman was pathogenic only for Aleutian mink and ADV-G was noninfectious. Trios of raccoons experimentally inoculated with ADV-TR and ADV-Utah all became infected with ADV, but only a single ADV-Pullman-inoculated raccoon showed evidence of infection. Furthermore, none of the ADV isolates induced pathological findings of AD in raccoons. Finally, when a preparation of ADV-TR prepared from infected raccoon lymph nodes was inoculated into mink and raccoons, typical AD was induced in Aleutian and non-Aleutian mink, but raccoons failed to show serological or pathological evidence of infection. These results indicated that raccoons can become infected with ADV and may have a role in the transmission of virus to mink but that raccoon-to-raccoon transmission of ADV is unlikely.

Aleutian Mink Disease↗