Specific in vitro biological activity of snake venom myotoxins

Some snake venoms contain toxins that are reported to be selective for damaging muscle. This specificity can be used to design experiments intended to eliminate muscle. We studied the small myotoxins and fractions IV and V of Bothrops nummifer venom to evaluate their direct effect on cultured muscle cells, neurons, macrophages, and a fibroblast cell line. The small myotoxins, at 100 micrograms/ml for 2 h, had no effect in vitro, contrary to the in vivo applications. Fractions IV and V were both myotoxic and, at 100 micrograms/ml, destroyed all cell types. However, at 10 micrograms/ml the effects of fraction IV were more selective for muscle. Vacuolation of the sarcoplasmic reticulum and T-tubules was first seen in the poisoned muscles, without initial lesions in the nuclei, sarcolemma, mitochondria, and rough endoplasmic reticulum. Fractions IV and V have different toxic activity in cells other than muscles and are a mixture of two basic proteins (i and ii). Protein ii is predominant in fraction IV and protein i is predominant in fraction V. The toxic effects may be mediated by the formation of nonspecific ionic pores in the sarcolemma and/or T-tubule muscle membrane.

Hepatitis C in liver allografts

Recurrent or intercurrent hepatitis C represents significant problems in patients with liver transplants and must be differentiated from hepatic allograft rejection and other conditions affecting allografts. Often, the currently available anti-hepatitis C virus (HCV) tests are not helpful in the differential diagnosis, because preexisting anti-HCV may persist after transplantation or its development may be delayed. We determined the presence of HCV RNA by the reverse double polymerase chain reaction in biopsy specimens of liver allografts from nine patients with acute or chronic hepatitis of uncertain origin and from three patients with cellular allograft rejection. The NS3 region sequences of HCV were detected in seven of nine liver allograft biopsy specimens 6 weeks to 20 months after transplantation. Hepatitis C virus RNA was not detected in two patients. One of these patients was anti-HCV positive, showing mild acute hepatitis 5 weeks after transplantation. Anti-HCV was present in three patients with detectable HCV RNA in the liver but was absent from four other patients with HCV RNA. These findings suggest that HCV is a major cause of acute and chronic hepatitis following liver transplantation, that detection of HCV RNA by polymerase chain reaction in the liver biopsy specimen represents a reliable method for the diagnosis of hepatitis C in liver allografts, and that in some patients HCV may be acquired during transplantation while in others it may represent a recurrent infection.

Liver resection under total vascular isolation. Variations on a theme

Total vascular isolation (TVI) of the liver was employed during parenchymal transection in 16 patients undergoing hepatic resection for large tumors (mean diameter, 10.7 cm) located near hilar structures, hepatic veins, or the inferior vena cava (IVC). In 14 cases, TVI was achieved by clamping the suprahepatic and infrahepatic IVC and the porta hepatis, with or without aortic occlusion; in two, selective hepatic vein clamping was possible, obviating IVC occlusion. Procedures included standard and extended right and left lobectomies and caudate lobe resections. Concomitant resection and reconstruction of the portal vein (one case), IVC (one case), and bile duct (three cases) was required. Postoperative hepatic and renal failure did not occur. Mean intensive care unit and hospital stays were 2.8 +/- 1.9 and 12.5 +/- 5.2 days, respectively. There were two perioperative deaths. Total vascular isolation permits safe resection of large, critically located tumors that would otherwise present prohibitive operative risks.

The potential relevance of growth hormone to female reproductive physiology and pathophysiology

OBJECTIVE

To assess possible interfacing between the somatotrophic and reproductive axes.

DESIGN

Literature review.

MAIN OUTCOME MEASURES

Ovarian growth hormone reception and action.

RESULTS

The available literature strongly supports a permissive role for the somatotrophic axis in the reproductive process.

CONCLUSIONS

Although a role for growth hormone in reproductive biology appears highly likely, its relevance to the process of puberty and to the normal workings of the menstrual cycle, as well as its possible application in reproductive pathology must await further investigation.

Human intraovarian interleukin-1 (IL-1) system: highly compartmentalized and hormonally dependent regulation of the genes encoding IL-1, its receptor, and its receptor antagonist

To delineate the scope of the human intraovarian IL-1 system we used a solution hybridization/RNase protection assay to test for expression of the genes encoding IL-1, its type I receptor (IL-1R), and its receptor antagonist (IL-1RA). IL-1 transcripts were not detected in whole ovarian material from days 4 or 12 of an unstimulated menstrual cycle but transcripts (IL-1 beta much greater than IL-11 alpha) were detected in preovulatory follicular aspirates from gonadotropin-stimulated cycles. Concurrently obtained peripheral monocytes did not contain IL-1 beta transcripts but macrophage-depleted follicular aspirates did, thus implicating the granulosa cells as the site of IL-1 expression. IL-1R transcripts were detected in RNA from whole ovaries and follicular aspirates but not in RNA from peripheral monocytes. IL-1RA transcripts were detected in whole ovarian material as well as in macrophage-free follicular aspirates. Cultured human granulosa and theca cells did not contain mRNA for IL-1 beta or IL-1RA but did contain mRNA for IL-1R. Treatment of cell cultures with forskolin (25 microM) induced IL-1 beta transcripts in granulosa but not theca cells. Forskolin also increased the basal levels of IL-1R transcripts in both granulosa and theca cells but did not induce IL-RA transcripts in either cell type. Taken together, these findings reveal the existence of a complete, highly compartmentalized, hormonally dependent intraovarian IL-1 system replete with ligands, receptor, and receptor antagonist.

Evidence for the production of a nonsteroidal endotheliotropic factor by human granulosa cells in culture

OBJECTIVE

To determine the cellular source of the angiogenic activity displayed by follicular fluid (FF).

DESIGN

Human granulosa cells were harvested from 27 follicular aspirates obtained 34 to 36 hours after eight patients, previously treated with human menopausal gonadotropin (hMG), follicle-stimulating hormone plus hMG, or clomiphene citrate and hMG received human chorionic gonadotropin (10,000 IU intramuscularly). Granulosa cells from individual follicles were plated at 50,000 cells/cm2 in Medium 199 (Sigma, St. Louis, MO) supplemented with either 5% calf serum or 0.1% bovine serum albumin; media collected 24 hours later was assayed in vitro measuring endothelial cell migration. Fractions depleted of steroids by reversed phase C1 chromatography were assayed as well.

RESULTS

Granulosa cell-conditioned media from 18 of 27 follicles significantly stimulated endothelial cell migration (P less than 0.05). Chemoattractant activity did not appear to be related to steroid accumulation in the media and was not diminished in steroid depleted fractions.

CONCLUSIONS

These findings suggest that human granulosa cells are a source of (nonsteroidal) endotheliotropic-angiogenic activity in FF.

Effects of midline medullary lesions on velocity storage and the vestibulo-ocular reflex

1. Crossing fibers were sectioned at the midline of the medulla caudal to the abducens nucleus in four cynomolgus monkeys. In two animals the lesions caused the time constant of horizontal and vertical per- and post-rotatory nystagmus to fall to 5-8 s. The slow rise in optokinetic nystagmus (OKN), as well as optokinetic after-nystagmus (OKAN) and cross-coupling of horizontal to vertical OKN and OKAN were abolished. Steady state velocities could not be maintained during off-vertical axis rotation (OVAR). Pitch and yaw nystagmus were affected similarly. We conclude that the ability to store activity related to slow phase eye velocity, i.e., "velocity storage", was lost in these monkeys for nystagmus about any axis. Velocity storage was partially affected by a small midline lesion in the same region in a third animal. There was no effect of a more superficial midline section in a fourth monkey, and it served as a control. 2. The gain (eye velocity/head velocity) of the vestibulo-ocular reflex (VOR) was unaffected by the midline lesions. Saccades were normal, as was the ability to hold the eyes in eccentric gaze positions. The gain of the fast component of OKN increased in one monkey to compensate for the loss of the slow component. 3. One animal was tested for its ability to adapt the gain of the VOR due to visual-vestibular mismatch after lesion. Average changes in gain in response to wearing magnifying (2.2x) and reducing (0.5x) lenses, were +35% and -30%, respectively. This is within the range of normal monkeys. Thus, a midline lesion that abolished velocity storage did not alter that animal's ability to adapt the gain of the VOR. 4. Lesions that reduced or abolished velocity storage interrupted crossing fibers in the rostral medulla, caudal to the abducens nuclei. Cells that contributed axons to this portion of the crossing fibers are most likely located in central portions of the medial vestibular nucleus (MVN) and/or in rostral portion of the descending vestibular nucleus (DVN). The implication is that velocity storage arises from neurons in MVN and DVN whose axons cross the midline.

[Complications of low-dose amiodarone]

Complications of low-dose amiodarone in 83 patients, in whom the drug was effective and who were followed for 1-13 years, are presented. Hypothyroidism was diagnosed in 11 (in 8 by the finding of elevated TSH). In 2 of the 3 in whom clinical signs of hypothyroidism were evident, amiodarone was continued, but thyroxine was also given. In 5 others thyrotoxicosis ensued. Propylthiouracil (PTU) was given and amiodarone was discontinued. PTU was then stopped within 4-8 months, without recurrence of the hyperthyroidism. In 1 patient pneumonitis resolved spontaneously a few weeks after stopping amiodarone. Because of gastrointestinal distress amiodarone was stopped in 1 patient. In none were liver enzymes elevated, nor was the nervous system affected clinically. Photosensitivity in 6 patients and skin discoloration in 2 did not necessitate discontinuation of the drug. Blurred vision was reported by 4, but its connection with amiodarone was not proven. There was sinus bradycardia in 2. There was no arrhythmic effect of amiodarone seen on ECG nor on Holter monitoring, nor was there any mortality. We conclude that amiodarone in low doses causes many complications, most of them mild and transient. However, in only a few cases is discontinuation of the drug indicated.

Isolation and characterization of herpes simplex virus resistant to nucleoside analogs

Herpes simplex virus type 1 was isolated from nine patients with herpes labialis who were not previously exposed to any antiviral agent. A significant variation in the growth of these isolates in BSC1 cells in the presence of 5-iodo-2'-deoxyuridine and acyclovir was observed. One of the isolates was highly resistant to 5-iodo-2'-deoxyuridine and acyclovir and failed to induce significant activity of thymidine kinase in cultures. Herpesvirus reisolated from the same patient 3 1/2 years later did not show significant changes in its resistance to acyclovir, suggesting that the patient has a latent infection with a drug-resistant virus.

Do prostaglandins lead to ovulation in the rabbit by stimulating proteolytic enzyme activity?

OBJECTIVE

To determine if prostaglandins (PGs) have a direct effect on the ovarian proteolytic enzyme system by examining ultrastructure of the follicle wall and the microvasculature in the presence and absence of indomethacin and by using the isolated perfused rabbit ovary.

DESIGN

Nine hours after administration of human chorionic gonadotropin (hCG) or hCG plus indomethacin, follicles were removed and processed for scanning and transmission electron microscopy. Isolated perfused rabbit ovaries were induced to ovulate with PGF2 alpha (100 ng/mL) in the presence and absence of tranexamic acid (0.1, 1.0, or 10 mM), a plasminogen activator inhibitor.

RESULTS

The addition of indomethacin to hCG inhibited ovulation and production of PGs without affecting the follicular microvasculature. However, the changes in follicle wall architecture were less pronounced after treatment with indomethacin. Ovulatory efficiency in response to PGF2 alpha (the percent of follicles greater than 1.5 mm that ovulate) was significantly reduced (P less than 0.01) by 10 mM tranexamic acid.

CONCLUSIONS

These results suggest that PGs induce follicular rupture by activation of proteolytic enzymes located in the follicle wall.

Increased circulating levels of bromocriptine after vaginal compared with oral administration

OBJECTIVE

To compare the circulating levels of bromocriptine after oral and vaginal administration of the drug.

DESIGN

Experimental

PARTICIPANTS

Seven ovulatory female volunteers and one hyperprolactinemic patient.

INTERVENTIONS

Ovulatory volunteers were randomized to receive either oral or vaginal bromocriptine (2.5 mg). In a second session, the subjects were crossed-over to bromocriptine by the alternate route. An additional hyperprolactinemic patient received vaginal bromocriptine only.

MAIN OUTCOME MEASURE

Serum bromocriptine and prolactin (PRL) levels were measured hourly for 12 hours in the normal volunteers and for 10 hours in the hyperprolactinemic patient.

RESULTS

Circulating bromocriptine levels were significantly higher after vaginal bromocriptine after the 7th hour (P less than 0.05). The reduction in serum PRL was significantly greater after oral administration between 2 and 6 hours.

CONCLUSIONS

Vaginally administered bromocriptine may result in a reduction in the overall dose required, thereby improving compliance without compromising therapeutic efficacy.

Synthesis and properties of some peptide analogues of actinomycin D

Analogues of actinomycin D (AMD) were synthesized in which amino acid replacements were made at various sites in the peptide moieties. These include (i) replacement of both N-methylvalines by N-methylleucine, (ii) replacement of both sarcosines by N-[2-(methoxycarbonyl)ethyl]glycine, and (iii) replacement of one or both D-valines by D-threonine. The purpose of replacements ii and iii was to ascertain the effect upon biological activity of introducing a new side chain which could be functionalized to allow the attachment of carrier molecules such as antibodies. NMR data indicated that none of the analogues had solution conformations significantly different from that of AMD. Difference spectra with DNA revealed that replacement i enhanced binding while the other analogues bound less strongly to DNA. All the analogues had lower antimicrobial activities than AMD. In contrast, 5,5'-(MeLeu)2AMD displayed in vitro antitumor activity comparable with that of AMD at approximately 100-fold lower concentrations.

Abdominal wall lipoma--CT and MRI appearance

Although soft tissue lipomata are common tumours, a large lipoma arising from the deep layers of the abdominal wall would appear to be excessively rare and the site of origin may be difficult to determine. The CT and MRI appearances of such a tumour are described.

A high-performance system for automation of the polymerase chain reaction

A high-performance PCR system has been developed which reduces the time required for PCR, increases the throughput, reduces reagent consumption and ensures reproducibility of amplification. Integration of sophisticated temperature control with optimally designed vessels has resulted in an amplification system which produces unique benefits. These include rapid amplification, the elimination of the need for oil, even for small volumes, and a microplate format which provides liquid handling automation benefits.

A comprehensive alternative to residential treatment for adolescents and young adults

This paper describes a treatment modality for adolescents and young adults who do not respond successfully to treatment within the family context. A comprehensive therapeutic program is implemented in the open community, providing benefits of residential care while avoiding many of the drawbacks. Five key components are discussed: creating individualized programs using community resources; effecting a complete separation from parents; maximizing autonomy and self-reliance; facilitating a corrective family experience; and capitalizing on transference in intensive individual psychotherapy, which is enhanced when a married couple functions as the treatment team. Suggestions for implementing this model are discussed and advantages and limitations are cited.

Spatial and temporal analysis by neurons in the representation of the central visual field in the cat's lateral suprasylvian visual cortex

We studied quantitatively the receptive-field properties of 74 units recorded from the representation of the central visual fields in the cat's lateral suprasylvian (LS) visual cortex. In agreement with previous workers, we found that LS receptive fields tended to be large and to lack discernible spatial structure. They resembled the complex receptive fields of areas 17 and 18 in their general organization. We examined the responses of these neurons to moving optimally oriented sinusoidal gratings that varied in spatial and temporal frequency of drift. Most LS neurons were selective for the spatial frequency of sinusoidal gratings; 7% responded to all spatial frequencies below a cutoff value. In agreement with previous reports, the optimal spatial frequencies for LS neurons covered a wider range than is seen in either area 17 or 18 alone (0.05-1 cycle/deg), but are certainly included in the range covered by both these afferent areas. Individual neurons in LS responded to a range of spatial frequencies broader than is typical for neurons in areas 17 and 18. The effect of varying the drift rate of otherwise optimal gratings was similar in LS to that reported for areas 17 and 18. Most neurons were optimally responsive to drift rates between 0.5 and 4 Hz, and resolved frequencies as high as 10-30 Hz. A few neurons had optima higher than 6 Hz and resolved frequencies in excess of 30 Hz. We conclude that the receptive fields of LS neurons reflect rather closely the properties of their afferents from areas 17 and 18.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcervical balloon tuboplasty. A multicenter study

Transcervical balloon tuboplasty represents a noninvasive technique to treat proximal tubal occlusion. In a multicenter study, 77 women with confirmed bilateral proximal tubal occlusion underwent the procedure. In 71 patients (92%), at least one proximally obstructed fallopian tube was recanalized. Concomitant distal bilateral tubal occlusions were diagnosed after successful proximal tubal balloon recanalizations in 13 patients (17%). In the remaining 64 patients, 22 clinical pregnancies (34%) have been confirmed during a median follow-up period of 12 months. Among those, 17 (77%) resulted in normal deliveries and five (23%) resulted in a first-trimester miscarriage. One patient was diagnosed with an ectopic pregnancy. Among 25 patients who had not conceived within 6 months of the procedure, 17 (68%) demonstrated continuing tubal patency on repeated hysterosalpingogram. We conclude that transcervical balloon tuboplasty is a safe outpatient technique that may represent an alternative to in vitro fertilization or microsurgical reanastomosis of fallopian tubes.

Selectivity for orientation and direction of motion of single neurons in cat striate and extrastriate visual cortex

1. We consider the consequences of the orientation selectivity shown by most cortical neurons for the nature of the signals they can convey about the direction of stimulus movement. On theoretical grounds we distinguish component direction selectivity, in which cells are selective for the direction of movement of oriented components of a complex stimulus, from pattern direction selectivity, or selectivity for the overall direction of movement of a pattern irrespective of the directions of its components. We employed a novel test using grating and plaid targets to distinguish these forms of direction selectivity. 2. We studied the responses of 280 cells from the striate cortex and 107 cells from the lateral suprasylvian cortex (LS) to single sinusoidal gratings to determine their orientation preference and directional selectivity. We tested 73 of these with sinusoidal plaids, composed of two sinusoidal gratings at different orientations, to study the organization of the directional mechanisms within the receptive field. 3. When tested with single gratings, the directional tuning of 277 oriented cells in area 17 had a mean half width of 20.6 degrees, a mode near 13 degrees, and a range of 3.8-58 degrees. Simple cells were slightly more narrowly tuned than complex cells. The selectivity of LS neurons for the direction of moving gratings is not markedly different from that of neurons in area 17. The mean direction half width was 20.7 degrees. 4. We evaluated the directional selectivity of these neurons by comparing responses to stimuli moved in the optimal direction with those elicited by a stimulus moving in the opposite direction. In area 17 about two-thirds of the neurons responded less than half as well to the non-preferred direction as to the preferred direction; two-fifths of the units responded less than one-fifth as well. Complex cells showed a somewhat greater tendency to directional bias than simple cells. LS neurons tended to have stronger directional asymmetries in their response to moving gratings: 83% of LS neurons showed a significant directional asymmetry. 5. Neurons in both areas responded independently to each component of the plaid. Thus cells giving single-lobed directional-tuning curves to gratings showed bilobed plaid tuning curves, with each lobe corresponding to movement in an effective direction by one of the two component gratings within the plaid. The two best directions for the plaids were those at which one or other single grating would have produced an optimal response when presented alone.(ABSTRACT TRUNCATED AT 400 WORDS)