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PubMedDate not supplied

Pars plana lensectomy by ultrasonic fragmentation. I. Versatile and simple technique for cataract removal.

A comparison has been made between pars plana lansectomy and intracapsular cataract extraction Pars plana lensectomy has been shown to have many advantages. It is applicable to any age, while intracapsular cataract extraction is restricted to patients over 30 years old. It can be used in any type of cataract, whereas intracapsular cataract extraction is restricted to senile cataracts. It requires less patient preparation, less instrumentation, and less surgical dexterity than does intracapsular cataract extraction. It allows intraocular examination at the time of surgery. It can be combined with other surgical procedures (intraocular lens implantation, vitrectomy, cryoretinopexy, scleral buckle, etc.). It leaves the eyes in better condition postoperatively with fewer postoperative complications, and it gives good or better visual results than intracapsular cataract extraction. It is now unnecessary to learn (and teach) multiple techniques to handle different ages and types of cataracts since pars plana lensectomy manages them all with fewer complications.

Adolescent↗
PubMed1993

Endocrine-like cells and insulin-binding sites in the epineurium of Helix pomatia.

Endocrine/paracrine-like cells are described for the first time in the epineurium of the cerebro-subesophageal ganglia connectives and in the epineurium of the nervus pallialis dexter et internus of Helix pomatia. At least a population of these cells contains insulin-immunoreactive material. Immunoelectron-microscopic investigations showed that electron-dense granules exhibit insulin-like material. Insulin-binding studies revealed granular cells as putative target-cells of insulin in the epineurium.

Animals↗
PubMed1981

An in vitro investigation of the hematopoietic microenvironment in young and aged mice.

Dexter-type cultures derived from the bone marrow of young and aged mice were established as in vitro correlates to the hematopoietic microenvironment and inoculated two weeks later with fresh bone marrow-derived stem cells (colony-forming units, CFUs) from young, syngeneic mice. Such cultures allowed the observation, quantitation and evaluation of interactions between aged or young microenvironments and the young stem cells. The hematopoietic microenvironments derived from aged marrow were found to support a greater total nucleated cellularity and a significantly greater number of CFUs. Also, the production of CFUs on aged monolayers occurred at an elevated rate. Though cyclic variations in total cellularity were noted in all cultures, the granulocyte--macrophage lineage always predominated. Lymphocyte populations in all cultures were seen to decline rapidly with time as other cell types became more abundant. The number of megakaryocytes in the aged marrow-derived cultures was significantly elevated in the early time periods post-refeeding. Differences in the adherent cell population densities were noted with the aged monolayers being somewhat less dense. However, there were no differences in morphologically identifiable cell types comprising the adherent layers derived from marrow of young and old mice. From these results, we conclude that there are differences in the ability of aged versus young hematopoietic microenvironments to support normal young stem cells in vitro and that the microenvironmental influences present in the in vitro system are reflective of those seen in the in vivo marrow microenvironment.

Aging↗
PubMed1991

Chronic central nervous system effects of acute organophosphate pesticide intoxication. The Pesticide Health Effects Study Group.

Acute organophosphate pesticide poisonings cause substantial morbidity and mortality world wide; however, whether organophosphates cause chronic neurological sequelae has not been established. To see whether single episodes of acute unintentional organophosphate intoxication lead to chronic neuropsychological dysfunction, we carried out a retrospective study of agricultural workers in Nicaragua who had been admitted to hospital between July 1, 1986, and July 31, 1988, for occupationally related organophosphate intoxication. This "poisoned" group (36 men) was tested on average about two years after the episode of pesticide poisoning and compared with a matched control group. The poisoned group did much worse than the control group on all neuropsychological subtests, with significantly worse performance on five of six subtests of a World Health Organisation neuropsychological test battery and on 3 of 6 additional tests that assessed verbal and visual attention, visual memory, visuomotor speed, sequencing and problem solving, and motor steadiness and dexterity. Differences in neuropsychological performance could not be explained by other factors. The findings of a persistent decrease in neuropsychological performance among individuals with previous intoxication emphasise the importance of prevention of even single episodes of organophosphate poisoning.

Acute Disease↗
PubMed1985

Further evidence for the existence of 'homing' receptors on murine leukemia cells which mediate adherence to normal bone marrow stromal cells.

A significant proportion of 131IUDR-labelled cells from murine leukemia cell lines L1210 and P388, but not the L5178Y lymphoma cell line, are retained in the bone marrow (B.M.) following i.v. injection into syngeneic mice. Following this, L1210 and P388 cells grow and rapidly replace the normal hematopoietic cells of the B.M. L1210 and P388 cells, but not several lymphoma cell lines, also bind avidly to monolayers of B.M. stromal cells (Dexter cultures) and soon overgrow the cultures following rapid cell proliferation. P388 cells bound equally well to confluent monolayers of B.M., whole mouse embryo and newborn mouse kidney while L1210 cells bound well to B.M. and whole mouse embryo but showed little binding to newborn kidney monolayers. The accumulation of the two leukemia cell lines in the B.M. was constant and indistinguishable over a 48-h period. In contrast, in both spleen and liver the number of L1210 cells decreased during the same period while P388 cells were retained at a constant level. Generally there was a lack of correlation of B.M. metastasis of a cell line and its metastasis to other organs although P388 cells, but not L1210 cells, demonstrated a tremendous capacity for metastatic growth in both spleen and liver. Normal B.M. cells were fused with the syngeneic SP2/0 murine myeloma fusor line and 10 hybridomas plus the SP2/0 parent were tested for in-vitro adherence to B.M. monolayers and in-vivo metastatic behavior. The same 3 (out of 10) hybridomas showed a high level of adherence to B.M. monolayers, high levels of retention of cells in the B.M. following i.v. injection, and rapid growth and takeover of the normal B.M. In marked contrast, neither the SP2/0 parent nor the remaining 7 hybridomas show significant adherence, B.M. retention or growth in the B.M. A distinct lack of correlation of B.M. vs liver or spleen metastasis was once again noted for the hybridomas although all of the hybridomas showed much less metastatic growth in the liver than the SP2/0 parent. Seven out of 10 hybridomas also showed less metastatic growth in the spleen including all 3 of the hybridomas which showed preferential growth in the B.M. Our data are consistent with the existence of cell surface 'homing' receptors on leukemia cells for normal B.M. stromal cells which function to retain the leukemia cells in the B.M. Such receptors might serve as functional markers for cell differentiation and leukemia classification.

Animals↗
PubMed1991

Multiple steps in the immortalization of cells of the B lineage.

The ability of A-MuLV to transform bone marrow cells on in vitro culture in agarose is enhanced by inclusion of conditioned media during infection and culture. The conditioned medium of a non-virus producing A-MuLV transformed fibroblast cell line was synergistic with medium from Whitlock-Witte long-term bone marrow cultures, while conditioned medium from modified Dexter-type cultures was not active. These media all contained growth promoting activity for bone marrow cells. There are two types of transformed colonies produced, and transformation of only one type was enhanced by inclusion of conditioned media. Analysis of this type of transformed cell showed them to be pre-B cells. Limiting dilution analysis suggests the transformation process to be dependent on two types of cells, one presumably the target and the second an "accessory cell". Models are presented to account for the factor-dependent in vitro transformation of pre-B cells.

Abelson murine leukemia virus↗
PubMed1996

Varieties of paw and digit movement during spontaneous food handling in rats: postures, bimanual coordination, preferences, and the effect of forelimb cortex lesions.

This study describes how rats use their paws and digits when handling a wide range of foodstuffs, including food pellets, grapes, sunflower seeds, shelled and unshelled peanuts, and different sized pastas, etc. Analysis of videorecordings show that the rats display digit postures that include variations in the spacing of the digits, differences in the relative use of different digits, and interlimb differences in paw and digit posture. The rats also display limb preferences in that one paw is used in a supporting function while the other rotates, flips, or pushes the food as is required by the shape of the item. There is a significant correlation between the paw used for manipulation and food items of similar shape but no correlation between the limb used for manipulation and that used for skilled reaching. Small unilateral lesions to the forepaw area of somatic sensorimotor cortex produced impairments in use of the paw contralateral to the lesions. These results: (1) reveal a surprising complexity in the way in which rats use their paws and digits in manipulating food; (2) show that rats have limb preferences in spontaneous food handling; and (3) show that manipulatory dexterity is dependent upon the integrity of the forelimb area of motor cortex. The results are discussed in relation to the evolution of motor skill, the use of rats for investigating questions of motor system organization, neural plasticity, and recovery of function after brain damage.

Animals↗
PubMed1994

Variables influencing worker compliance with universal precautions in the emergency department.

BACKGROUND: Emergency department health care workers frequently provide care to patients who are in unstable condition, bleeding, or in a crisis situation. To identify the variables described in the Health Belief Model affecting health care workers' compliance with practices and devices believed to reduce exposure to patients' blood, the staff of a level II trauma center were surveyed for knowledge, compliance, and training regarding universal precautions. METHODS: Fifty-three health care workers responded to an anonymous, self-report, 50-item questionnaire. Significant differences in mean scores were determined by use of a two-tailed t test. RESULTS: Health care workers estimated they were most likely to perform handwashing after contact with body fluids and to wear gloves if contact with blood was anticipated. The most common obstacles to compliance with universal precautions were lack of time, patients perceived to be at lower risk for HIV or hepatitis B infections, and interference with technical skills. Health care workers with more than three perceived obstacles to universal precautions were less likely to use gloves (p < 0.05) if contact with blood was anticipated. Health care workers with a higher number of training experiences in universal precautions were more likely to use gloves if contact with blood was anticipated (p < 0.05) and less likely to recap a needle after giving an intravascular injection (p < 0.05), drawing a blood gas sample (p < 0.05), or injecting medication into an intravenous line (p < 0.05). CONCLUSIONS: The application of the Health Belief Model to this problem suggests that an integrated approach is appropriate. Such an approach should incorporate engineering controls, cognitive approaches, behavior modification strategies, and training experiences to improve skills and dexterity.

Blood-Borne Pathogens↗
PubMedDate not supplied

Sensory control of a multifunction hand prosthesis.

The current generation of prostheses that are fitted to limb deficient individuals have only a single degree of freedom which limits their functional range. Furthermore, electrically powered prostheses have a limited user input. Electrical signals generated by the contraction of muscles in the user's stump open and close the hand in an 'on and off' fashion. Since the only feedback is visual, the prostheses tend to be used less dexterously than body powered devices. A different approach has been adopted by the Control Engineering Group at Southampton University. They have retained a single electromyographic input channel, but added sensory feedback to an electronic controller, which decides on the grip posture and tension. Satisfactory operation of the hand depends on the sensors employed. A review of transducers used on previous prostheses at Southampton is followed by a description of recent sensor developments. Finally the intentions for a new generation of prostheses are outlined. These include combining sensory input with an integrated circuit microcontroller to provide a more reliable system.

Biomedical Engineering↗
PubMed1990

Neurovascular island flap by the disconnecting-reconnecting technique.

The authors report nine cases of hetero-digital neurovascular island flaps raised by the "disconnecting-reconnecting" technique for defects of the tactile pad of the thumb. At an average follow-up of 25 months, all cases had good restoration of sensibility without any "double sensibility" phenomenon and patients regained good dexterity. No tender neuromata developed and donor site complications were not troublesome.

Adolescent↗
PubMed1978

Neurotoxic response of infant monkeys to methylmercury.

Four infant monkeys were dosed orally with 500 microgram Hg/kg body wt./day /as methylmercury (MeHg) chloride dissolved sodium carbonate) beginning at 1 day of age. Neurological and behavioral signs of MeHg toxicity and blood Hg levels were monitored weekly. At first sign of MeHg intoxication, dosing with MeHg was terminated and the infants were monitored to assess reversal of the signs of MeHg toxicity. The first signs of MeHg toxicity, exhibited as a loss in dexterity and locomotor ability, were observed after 28--29 days of treatment; the blood Hg levels were 8.0--9.4 microgram Hg/g blood. Dosing was terminated at 28--29 days of treatment but the signs of MeHg toxicity continued to develop. The infants became ataxic, blind, comatose and were necropsied at 35--43 days after initiating treatment with MgHg. The mercury concentrations in tissues analyzed after necropsy were highest in liver (55.8 +/- 3.2 microgram Hg/g) followed by occipital cortex (35.6 +/- 4.8 microgram Hg/g) renal cortex (32.8 +/- 1.6 microgram Hg/g). The frontal and temporal cortices had 27.0 +/- 3.4 and 29.6 +/- 4.9 microgram Hg/g respectively while the cerebellar Hg concentration averaged 13.0 +/- 1.5 microgram Hg/g. The mean blood/brain ratio was 0.21 +/- 0.4. Histopathologic lesions were marked in the cerebrum with less severe lesions in the cerebellar nuclei. The Purkinje and granular cells of the cerebellar vermis appeared histologically normal. Lesions were not observed in the peripheral nervous system. The signs of MeHg intoxication, the tissue distribution of MeHg and histopathologic lesions observed in the infant monkeys were similar to those reported for adult monkeys.

Animals↗
PubMed1995

Evaluation of cognitive function in patients with limited small cell lung cancer prior to and shortly following prophylactic cranial irradiation.

PURPOSE: Cognitive deficits after treatment for small cell lung cancer (SCLC) have been attributed to prophylactic cranial irradiation (PCI). A prospective study of neuropsychological function was undertaken to document the evolution and magnitude of neuropsychologic deficits. METHODS AND MATERIALS: Thirty patients with limited stage SCLC who responded well (29 complete response (CR), 1 partial response (PR)) to combination chemotherapy plus thoracic irradiation or resection were studied with neuropsychological tests in the cognitive domains of intelligence, frontal lobe function, language, memory, visual-perception, and motor dexterity prior to a planned course of PCI. Nine patients had a neurologic history that could influence testing. RESULTS: An unexpected 97% (29 out 30) of patients had evidence of cognitive dysfunction prior to PCI. The most frequent impairment was verbal memory, followed by frontal lobe dysfunction, and fine motor incoordination. Of the patients with no prior neurologic or substance abuse history, 20 out of 21 (95%) had impairments on neuropsychological assessment. This neurologically normal group was just as impaired as the group with such a history with respect to delayed verbal memory and frontal lobe executive function. Eleven patients had neuropsychological testing 6 to 20 months after PCI; no significant differences were found from their pretreatment tests. CONCLUSIONS: A high proportion of neurologically normal patients was limited SCLC and favorable responses to combination chemotherapy have specific cognitive deficits before receiving PCI. Short-term (6 to 20 months) observations after PCI have shown no significant deterioration.

Adult↗
PubMed1992

Trapeziometacarpal joint arthrodesis: a functional evaluation.

Over a 10-year period, 39 trapeziometacarpal (TM) joint fusions were performed in 37 patients. Pin fixation was used in 27 fusions and staple fixation in 12; all were bone grafted. There were five delayed unions (greater than 3 months) and three nonunions. Twenty-four fusions were evaluated at an average of 4 years. Subjectively, there were 11 excellent, 7 good, 5 fair, and 1 poor result. Grip and pinch strength were symmetrical, and the nine-hole peg test (a measurement of dexterity) was slightly better on the treated side. X-ray films were taken and compared with 25 normal films to assess metacarpal mobility. There was a 72% reduction in the adduction/abduction arc and a 61% reduction in the flexion/extension arc. Despite the marked decrease in motion, subjective functional complaints were minimal. X-ray films were evaluated independently by a radiologist to assess progression of degenerative changes. Only two patients were noted to have changes at the scaphotrapezial joint.

Activities of Daily Living↗
PubMedDate not supplied

Influence of cutting edge configuration on surgical needle penetration forces.

A standardized test for measuring the needle penetration forces has been developed that can be easily replicated in any laboratory. Using this test, conventional cutting edge needles utilized in the test produced lower penetration forces than reverse cutting edge needles. The lower penetration forces encountered by the conventional cutting edge needles imply that the physician should be able to handle these needles with more dexterity and precision than the reverse cutting edge needle.

Membranes, Artificial↗
PubMed1992

The stability of neuropsychological test performance in a group of parenteral drug users.

The stability of neuropsychological performance in a sample of drug abusers was investigated for a wide range of neuropsychological tests, using a test-retest paradigm with 16 parenteral drug users. The battery administered included tests of general intellectual function, abstract reasoning, verbal memory, language, attention, visuospatial ability, set switching, speeded performance, and manipulative dexterity. Stability coefficients were of a moderate to high magnitude for most of the tests and were comparable to coefficients found in other studies of non-drug-users. Two exceptions, however, were the Selective Reminding Test and the Perdue Pegboard. Possible reasons for instability with these two tests are discussed. It is concluded that neuropsychological investigations of drug abusers can yield consistent and reliable data, although further studies should employ alternative and/or supplementary measures of verbal memory and motor function.

Adult↗
PubMed1993

Augmented production of interleukin 6 by co-culture of human bone marrow adherent cells and human leukemic cells.

Human Dexter-type culture of bone marrow (BM) cells maintains long-term hematopoiesis in the presence of an adherent stromal layer. These BM adherent cells produce hematopoietic growth factors constitutively or inducively and support developing hematopoietic cells. To elucidate the ability of cytokine production by BM adherent cells, the cytokine levels of the culture supernatant of BM adherent cells were measured by enzyme-linked immunosorbent assays. Constitutive production of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 6 (IL-6) by the unstimulated BM adherent cells was demonstrated. Levels of granulocyte colony-stimulating factor (G-CSF) were below detectable levels (< 10 pg/ml). The IL-6 level was significantly increased in the co-culture supernatant with KG1 cells or U937 cells (P < 0.01: P < 0.05, respectively). Even when the adherent cells and cell line cells were separated by a membrane filter, the IL-6 level was significantly higher than the control culture (P < 0.01). Co-culture with these cell lines was supposed to induce the increased production of IL-6, which was mediated by some soluble cytokines. The GM-CSF level was not increased in the supernatant co-cultured with any of the cell lines, except with K562 cells. However, K562 cells alone secreted a detectable level of GM-CSF and the increased level of GM-CSF was considered to be due to the production of GM-CSF by K562 cells. G-CSF was not detectable in the supernatant co-cultured with any cell line cells. This result indicates that the cytokine production was regulated by the interaction of BM adherent cells and some leukemic cells.

Bone Marrow↗
PubMed1992

Compliance with infection control procedures among California orthodontists.

We conducted a survey of a random sample of California orthodontists and of general dentists to compare their infection control procedures. Questionnaires were returned by 124 orthodontists (56% response rate) and 126 general dentists (61% response rate). Eighteen questions were asked covering practice profile, perception of risk from hepatitis B virus (HBV) and human immunodeficiency virus (HIV), exposure to blood, barrier protection used, and sterilization and disinfection procedures. Gloves always were worn by 80% of the orthodontists sampled, 63% always wore glasses, and 59% changed gloves between patients. Orthodontists sterilized their instruments 66% of the time and pliers 49% of the time. Compared with general dentists, orthodontists' perception of risk, use of barrier protection, and sterilization and disinfection procedures were lower in all areas. Our data suggest that poorer performance may be because orthodontists: (1) perceive their younger population of patients at less risk for HBV and HIV; (2) treat 2.5 times as many patients, which increases the costs of infection control; (3) do not use invasive procedures; and (4) perceive that glove use decreases dexterity. Orthodontists should follow the American Dental Association/Council on Dental Therapeutics infection control guidelines for universal precautions. To meet these guidelines, orthodontists still need improvement in all aspects of their infection control procedures.

Adolescent↗
PubMedDate not supplied

Psychological effects of subclinical epileptiform EEG discharges. I. Scholastic skills.

The possible effects of subclinical epileptiform EEG discharges on educational skills have been studied. Twenty children with proven or suspected epilepsy and known subclinical EEG discharges underwent telemetric EEG and video monitoring during standard tasks of reading, mental arithmetic and manual dexterity, and at rest. The discharge rate was significantly lower at rest than during execution of a task. For both reading and arithmetic, the discharge rate was higher when the child was presented with material appropriate to his own level of ability than when easier or more difficult material was given. High discharge rates were associated with low test performance particularly for arithmetic. Reading speed was significantly increased during the discharges, but overall reading efficiency was significantly reduced with respect to the non-discharge condition. The decrement of reading efficiency was greater for longer than for shorter discharges. The findings confirm that otherwise subclinical EEG discharges may be accompanied by momentary impairment of scholastic skills. The interaction between discharges and cognitive function is, however, complex and the nature and level of difficulty of the task in turn affects the rate of EEG discharge.

Child↗