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Biomedical subjects

R Sandler

Publications and source records attributed to R Sandler.

At least 19 recordsLinked to original sources
PubMed2000

Impact severity in self-initiated sits and falls associates with center-of-gravity excursion during descent.

Although the energy available during a fall from standing greatly exceeds that required to produce hip fracture, this occurs in only about 2% of falls in the elderly. This is thought to be due in part to one's ability to reduce the vertical impact velocity (nu(nu)) and kinetic energy (KE(nu)) of the body through energy absorption in the lower extremity muscles during descent. The present study tested the hypothesis that the magnitude and percent attenuation in nu(nu) and KE(nu) associate with the horizontal and vertical excursion of the body's center-of-gravity during descent. Measures were acquired of whole-body kinematics and lower extremity kinetics as young subjects underwent backward descents involving vertical drops of either thigh length (SIT) or lower extremity length (FALL), and horizontal pelvis excursions of either 33 or 66% of lower extremity length. In all trials, subjects attempted to "land as softly as possible." While attenuation in nu(nu) and KE(nu) (which averaged 62 and 92% respectively), did not associate with trial type, raw magnitudes of these parameters did, with nu(nu) averaging 2-fold greater, and KE(nu) averaging 6-fold greater, in 66% FALL than in 33% SIT or 66% SIT trials. This was due to a rapid increase in downward velocity accompanying the final stage of descent in 66% SIT and 66% FALL trials, which coincided with the knee moving posterior to the ankle. Accordingly, severe impacts likely accompany not only large fall heights, but also falls where the feet are thrown rapidly forward, as during a backward slip.

Accidental Falls↗
PubMed2000

Prevention of falls and fall-related fractures through biomechanics.

Falls and fall-related injuries are a major health problem for elderly people. Biomechanical studies provide important insight into the cause of such events and reveal new techniques for preventing them. The topics reviewed in this article include balance recovery, safe landing responses, impact forces during falls, and fracture prevention through exercise programs, hip pads, and energy-absorbing floors.

Accidental Falls↗
PubMed1998

Psychological morbidity and HIV in Kenya.

This paper describes a cross-sectional study with subjects and raters blind to HIV status to assess psychiatric morbidity associated with HIV in a sample of working adults in Western Kenya. Subjects were recruited from an occupational health clinic for statutory annual health checks of workers in the food industry. Psychiatric interviews and neuropsychological tests were conducted. Of 230 subjects, 34% were HIV positive. Women had a higher rate than men, and those who worked as bargirls or were divorced, widowed or separated were particularly at risk. There were no substantial differences in psychiatric morbidity or neuropsychological functioning between the HIV-positive and HIV-negative subjects.

AIDS Dementia Complex↗
PubMed1997

Pilot study of free and conjugated urinary mutagenicity during consumption of pan-fried meats: possible modulation by cruciferous vegetables, glutathione S-transferase-M1, and N-acetyltransferase-2.

Epidemiological and experimental evidence indicates that consumption of fried meats in conjunction with certain genotypes of phase I and II metabolism genes poses an elevated risk for colorectal cancer. Parallel to this, the consumption of cruciferous vegetables is associated with a reduced risk of colon cancer. Therefore, we designed a 6-week pilot feeding study to evaluate the effect of these variables on urinary mutagenicity, which is a biomarker associated with fried-meat consumption. Eight subjects were fed fried meats daily for six weeks; four ate cruciferous vegetables, and four ate non-cruciferous vegetables. Urinary mutagenicity was evaluated in the presence of S9 in strain YG1024 of Salmonella, which is a frameshift strain that overproduces acetyltransferase. C18/methanol extracts of 24-h urines collected once each week were tested unhydrolyzed (free mutagenicity) and hydrolyzed (total mutagenicity); the difference between the two was the conjugated mutagenicity. Although not significant, the levels of conjugated urinary mutagenicity doubled among crucifera consumers and decreased to 30% of the initial levels among non-crucifera consumers, suggesting the possibility that crucifera may enhance the level of conjugated urinary mutagenicity resulting from consumption of fried meats. Such an effect would be consistent with the documented ability of cruciferous vegetables to induce phase II enzymes. The NAT2 rapid phenotype was significantly associated with approximately 2-fold increases in conjugated (p = 0.05) and total (p = 0.004) urinary mutagenicity relative to NAT2 slow subjects, consistent with the elevated risk confirmed by the NAT2 rapid phenotype for colorectal cancer among meat consumers. An approximately 2-fold increase in urinary mutagenicity among the GSTM1- subjects relative to the GSTM1+ subjects approached significance for free (p = 0.18) and total (p = 0.13) urinary mutagenicity. This is the first report on (a) the mutagenicity of hydrolyzed urine, which was consistently more mutagenic than unhydrolyzed urine; (b) the potential enhancement of conjugated urinary mutagenicity by crucifera; and (c) the association of the rapid NAT2 and possibly the GSTM1- phenotype with elevated levels of fried meat-associated urinary mutagenicity.

Aged↗
PubMed1995

Calcium supplementation and rectal mucosal proliferation: a randomized controlled trial.

BACKGROUND: Data from studies using rodents suggest that dietary calcium inhibits bile acid-induced mucosal damage and experimental carcinogenesis in the large bowel. However, in humans, the effect of dietary calcium and calcium supplementation on proliferation and carcinogenesis in the large bowel has been unclear. PURPOSE: To assess the effect of calcium supplementation on rectal mucosal proliferation in humans, we conducted a multicenter, randomized, placebo-controlled, double-blinded trial. METHODS: Participants were part of a larger multicenter chemoprevention trial; all were at high risk for large-bowel neoplasia, with at least one large-bowel adenoma removed endoscopically within the 3 months before study entry but with no known polyps remaining. Subjects were randomly assigned to receive daily either 3000 mg of calcium carbonate (providing 1200 mg elemental calcium) or an identical-appearing placebo tablet. During a scheduled endoscopy 6-9 months after random assignment (approximately 1 year after the qualifying endoscopy), rectal mucosal samples were obtained from 333 patients (173 assigned to calcium and 160 assigned to placebo). Proliferating cell nuclear antigen (PCNA) labeling indices (LIs) were computed as the measure of proliferation in specimens from 146 patients receiving calcium and 129 patients receiving placebo. Bromodeoxyuridine (BrdU) labeling was used to measure proliferation in a smaller number of specimens (27 calcium-receiving and 31 placebo-receiving participants). For each scorable crypt having at least one labeled cell (or surrounded by crypts with at least one labeled cell), a crypt LI was calculated as the number of labeled cells divided by the total number of crypt cells. Crypt LIs were averaged to produce a participant's average LI. RESULTS: The overall unadjusted mean PCNA LIs (+/- SE) were similar in the calcium and placebo groups (3.85% +/- 0.08% versus 3.92% +/- 0.08%, respectively, P = .30). The overall unadjusted mean BrdU LIs (+/- SE) were 3.88% +/- 0.30% in the calcium group and 3.54% +/- 0.21% in the placebo group (P = .54). PCNA labeling indices in the most luminal 40% of the crypt were small but, if anything, were higher in the calcium group. There was no patient subgroup within which calcium had an antiproliferative effect; the overall findings persisted among patients with high and low calcium intake, high and low fat intake, and high and low fiber intake. CONCLUSIONS: Calcium supplementation does not decrease rectal mucosal proliferation, as measured by PCNA (and BrdU) immunohistochemistry, in patients with previous large-bowel adenomas. This study, therefore, does not provide evidence for an anticarcinogenic effect of calcium.

Adenoma↗
PubMed1995

Aminosyn PF or trophamine: which provides more protection from cholestasis associated with total parenteral nutrition?

Cholestasis often occurs in infants on total parenteral nutrition (TPN) for long periods. Amino acid formulations developed specifically for infants, namely Aminosyn PF and Trophamine, may protect against cholestasis associated with total parenteral nutrition (CATPN). The development of cholestasis may also be caused by other risk factors such as prematurity, surgery, sepsis, and extracorporeal membrane oxygenation (ECMO). To evaluate the relative effectiveness of the pediatric amino acid formulations in reducing CATPN, the courses of 70 infants < 1 year of age who received TPN for at least 14 days were reviewed. Cholestasis was defined as a conjugated serum bilirubin > or = 2 mg/dl subsequent to the initiation of TPN; CATPN was considered present when other factors related to cholestasis were ruled out. Liver function tests were recorded 24 h before starting TPN and at day 7, 15, and 21 during TPN infusion. Thirty infants (42.8%) developed cholestasis. CATPN was judged to have occurred in 15 (21.4%) of 70 infants, while 15 (21.4%) developed cholestasis secondary to other factors. Of the 15 CATPN patients, 7 had received Trophamine, 6 had received Aminosyn PF, and 2 had received both solutions. Aminosyn PF and Trophamine, along with other potential risk factors for CATPN such as antecedent surgery, sepsis, ECMO, prematurity, and nitrogen/calorie intake were analyzed by regression-analysis methods. None was statistically significant except the length of TPN (p = 0.0063). In conclusion, we cannot support the view that Trophamine is more effective than Aminosyn PF in the prevention of CATPN.

Amino Acids↗
PubMed1994

Prevention of gram-positive sepsis in neonates weighing less than 1500 grams.

A prospective, randomized study to evaluate the effectiveness of a continuous low-dose vancomycin infusion to prevent nosocomial gram-positive bacteremia was initiated within the first 2 weeks of life in neonates weighing < 1500 gm. Seventy-one infants received constant infusion of vancomycin (25 micrograms/ml) mixed with their total parenteral nutrition solution; 70 infants served as control subjects. The groups were clinically similar in birth weight, estimated gestational age, and severity of illness. Administration of vancomycin was begun at a mean age of 5.4 +/- 2.9 days. Infants had mean serum vancomycin concentrations of 2.4 micrograms/ml, and received vancomycin for a mean of 11 +/- 7 days. No vancomycin-resistant organisms were detected in surveillance cultures during the 2-year study period. Twenty-four of seventy control infants, in comparison with 1 of 71 infants receiving vancomycin, had gram-positive bacteremia (p < 0.001). The addition of a low dose of vancomycin to alimentation fluids virtually eliminated the incidence of gram-positive bacteremia in an at-risk population of very low birth weight infants. However, the widespread use of vancomycin in total parenteral nutrition solution is not recommended until better data on the emergence of vancomycin-resistant organisms are available.

Bacteremia↗
PubMed1991

Coexistence of GABA and glutamate in mossy fiber terminals of the primate hippocampus: an ultrastructural study.

One of the links in the trisynaptic circuit of the hippocampus is the synapse between the mossy fibre terminals of dentate granule cells and CA3 pyramidal cells of Ammon's horn. This synapse has been physiologically characterized as excitatory, and there is pharmacological and immunohistochemical evidence that mossy fibre terminals utilize glutamate as a neurotransmitter. This study demonstrates the presence of GABA-immunoreactivity in mossy fibre axons and terminals of the monkey at the electron microscopic level. We combined Golgi impregnation to identify CA3 pyramidal neurones, with postembedding immunocytochemistry to characterize the inputs to the identified cells. GABA immunoreactivity was present in mossy fibre terminals that made synaptic contact with complex embedded spines of identified Golgi-impregnated CA3 pyramidal neurones. GABA immunoreactivity could be demonstrated in serial sections of the same mossy fibre terminals by using 3 different antisera raised against GABA. In serial sections, the mossy fibre terminals were shown to be immunoreactive for both glutamate and GABA. In contrast, glutamate immunoreactivity but not GABA immunoreactivity was found in other terminals that did not have the morphological characteristics of mossy fibre terminals. GABA immunoreactivity in mossy fibre terminals was also demonstrated in a human surgical specimen of hippocampus. The coexistence of an "excitatory" amino acid and of an "inhibitory" amino acid in the same "excitatory" nerve terminal raises the possibility of corelease of the two transmitters, suggesting that the control of hippocampal neural activity is more complex than hitherto suspected.

Adolescent↗
PubMed1988

Characterization of receptors for a T cell derived cytosolic BCGF-60kD.

A 60 kD cytosolic protein derived from human peripheral blood T cells has been shown to mediate proliferation in BCGF responsive long term B cell cultures. In this report, we show cBCGF-60kD can be radioiodinated with no significant loss of biologic activity and bound specifically to B cell surface membrane receptors. The time course of 125I-cBCGF-60kD demonstrated that binding reached saturation within 40 minutes, (T 1/2 of 15 minutes). Scatchard analyses of ligand-receptor binding identified a high affinity receptor (0.6(-3) x 10(3) receptors per cell) having a dissociation constant of 1-8 pM. Partial cross-competition experiments with a secreted, T cell derived BCGF-12kD identified a potential receptor heterogeneity on BCGF responsive B cell line.

B-Lymphocytes↗
PubMed1987

The outcome of psychiatric illness. A 2-year follow-up study.

A 2-year follow-up of 328 patients discharged from a psychiatric hospital was carried out to determine the presence and severity of symptoms, disturbed behaviour and functional disability and to assess social performance. Population groups and diagnostic entities (schizophrenia, affective illness, acute and chronic organic brain syndromes and functional non-psychotic conditions) were compared. In general the proportion of patients with symptoms was considerable at discharge in respect of both the diagnostic entities and the population groups, and decreased on follow-up. Disturbed behaviour abated on discharge, but the prevalence of functional incapacity remained high. The pattern for different diagnostic groups was more or less the same, but the proportions differed in some instances. These are discussed in detail. The problem of sequelae of psychiatric illness in patients discharged from a psychiatric hospital is shown to be considerable.

Acute Disease↗
PubMed1986

Admissions to a psychiatric hospital. Factors associated with admission and inpatient care.

A detailed cross-cultural analysis was carried out of demographic, social, family and diagnostic variables responsible for, or associated with, the admission of 460 sequentially admitted patients to an area psychiatric hospital (Valkenberg Hospital). All patients were socio-economically disadvantaged compared with the population from which they were drawn and socio-economic factors played a significant part in admission. Larger proportions of coloured and black schizophrenics and substance abusers were admitted, and this is related to socio-economic conditions and the fact that the population generally are younger. There were indications that the period of inpatient stay, particularly for coloured and black patients, was too short in many cases for meaningful preparation for discharge, and that supervision after discharge was inadequate. Treatment of the type offered by this hospital appears largely to achieve the diminution or control of aberrant or difficult behaviour and symptoms while functional impairment is little improved.

Adult↗
PubMed1986

Readmissions to a psychiatric hospital. Outcome on follow-up.

Readmissions to South African psychiatric hospitals form 45% of their intake and constitute a considerable burden on staff and facilities. The situation was investigated in a series of 460 patients sequentially admitted to a large, actively admitting hospital (Valkenberg Hospital, Cape Town). There was a difference in the proportion of readmissions within 1 year for different population groups--26,5% for white, 41% for coloured and 42% for black patients. The factors influencing this are explored. There was a marked difference in diagnoses--schizophrenics and affective disorders being more common in the black and coloured cohorts. Possible reasons for this are discussed. A 2-year post-discharge follow-up study showed a marked and sustained fall in the severity of psychiatric symptoms and difficult behaviour for all cohorts, but not of functional impairment, which was present in approximately 90% of all patients. Adequate aftercare and rehabilitation facilities in the community are evidently lacking.

Female↗
PubMed1986

Parkinsonian symptoms in tardive dyskinesia. A prevalence study.

Of 49 unselected patients with tardive dyskinesia (TD) 28 (57%) exhibited various parkinsonian signs. Isolated tremor was encountered in 11 patients, tremor with hypokinesia and rigidity in 13 patients, and hypokinesia and rigidity alone in 4. Tremor was detected among patients with scorable peripheral signs of TD. Hypokineto-rigidity, with or without tremor, was attributed to high doses of neuroleptics--notably fluphenazine. This study confirmed reports that isolated parkinsonian signs occurring concurrently with TD must be considered a regular phenomenon even when questionable cases (e.g. tremor in lithium-treated patients, action-tremor in the elderly) are disregarded. However, given the 'fragmentation' of the parkinsonian syndrome, often atypical tremor and signs of anosognosia in TD patients, the final diagnosis may necessitate pharmacological testing (discontinuation of neuroleptic medication, administration of anticholinergics).

Aged↗
PubMed1985

The rise in readmissions to psychiatric hospitals.

The progressive increase in readmissions to psychiatric hospitals in South Africa is causing concern. Readmissions now amount to 42% of total admissions, and in some cases their number exceeds that of first admissions. The phenomenon has been identified as occurring overwhelmingly among short-stay patients. Factors associated with readmissions have been examined as the first part of an ongoing investigation. Among these are a decline in available beds, an increasing shortage of psychiatric staff, differing readmission rates for different population groups, and the tendency of certain types of psychiatric disorders to relapse more frequently (schizophrenia and affective illness). The inability of the present psychiatric outpatient and community services to lower the readmission rate has been demonstrated. Factors which may have a bearing on the situation such as socio-economic conditions, substance abuse, compliance with medication and rehabilitative services are discussed.

Black or African American↗