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Biomedical subjects

M C Gupta

Publications and source records attributed to M C Gupta.

At least 19 recordsLinked to original sources
PubMed2001

S1 screw bending moment with posterior spinal instrumentation across the lumbosacral junction after unilateral iliac crest harvest.

STUDY DESIGN: A biomechanical study comparing fixation across the lumbosacral junction. OBJECTIVES: To determine which long posterior construct across the lumbosacral junction produces the least bending moment on the S1 screw when only one ilium is available for fixation. SUMMARY OF BACKGROUND DATA: Recent in vitro studies have demonstrated the benefit of anterior support and fixation into the ilium when instrumenting a long posterior construct across the lumbosacral junction. METHODS: Four L2-sacrum constructs were tested on six synthetic models of the lumbar spine and pelvis simulating that the right ilium had been harvested. Construct 1: L2-S1 bilateral screws. Construct 2: L2-S1 + left iliac bolt. Construct 3: L2-S1 + left iliac bolt + right S2 screw. Construct 4: L2-S1 + bilateral S2 screws. The four constructs were then retested with an anterior L5-S1 strut. A flexion-extension moment was applied across each construct, and the moment at the left and right S1 pedicle screw was measured with internal strain gauges. RESULTS: Iliac bolt fixation was found to significantly decrease the flexion-extension moment on the ipsilateral S1 screw by 70% and the contralateral screw by 26%. An anterior L5-S1 strut significantly decreased the S1 screw flexion-extension moment by 33%. Anterior support at L5-S1 provided no statistical decrease in the flexion-extension moment when bilateral posterior fixation beyond S1 was present with either a unilateral iliac bolt and contralateral S2 screw, or bilateral S2 screws. CONCLUSIONS: There is a significant decrease in the flexion-extension moment on the S1 screw when extending long posterior constructs to either the ilium or S2 sacral screw. There is no biomechanical advantage of the iliac bolt over the S2 screw in decreasing the moment on the S1 screw in flexion and extension. Adding anterior support to long posterior constructs significantly decreases the moment on the S1 screw. Adding distal posterior fixation to either the ilium or S2 decreases the moment on S1 screws more than adding anterior support. Further, adding anterior support when bilateral distal fixation past S1 is already present does not significantly decrease the moment on the S1 screws in flexion and extension.

Bone Screws↗
PubMed2001

The role of acute decompression and restoration of spinal alignment in the prevention of post-traumatic syringomyelia: case report and review of recent literature.

STUDY DESIGN: Case report. INTRODUCTION: Acute post-traumatic syringomyelia formation after spinal cord injury has been considered a rare complication. At this writing, most recent reports have surfaced in neurosurgical journals. As an entity, post-traumatic syringomyelia has not been widely appreciated. It has been confused with conditions such as Hansen's disease or ulnar nerve compression at the cubital tunnel. One study also demonstrated that the occurrence of syrinx is significantly correlated with spinal stenosis after treatment, and that an inadequate reduction of the spine may lead to the formation of syrinx. This reported case describes a patient in whom post-traumatic syringomyelia began to develop 3 weeks after injury, which improved neurologically after adequate decompression. SUMMARY OF BACKGROUND DATA: A 30-year-old man sustained a 20-foot fall at work. He presented with a complete spinal cord injury below T4 secondary to a T4 fracture dislocation. The patient underwent open reduction and internal fixation of T1-T8. After 3 weeks, the patient was noted to have ascending weakness in his bilateral upper extremities and some clawing of both hands. METHODS: A computed tomography myelogram demonstrated inability of contrast to pass through the T4-T5 region from a lumbar puncture. An incomplete reduction was noted. The canal showed significant stenosis. A magnetic resonance image of the patient's C-spine showed increased signal in the substance of the cord extending into the C1-C2 area. The patient returned to the operating room for T3-T5 decompressive laminectomy and posterolateral decompression including the pedicles, disc, and posterior aspect of the body. Intraoperative ultrasound monitoring showed a good flow of cerebrospinal fluid past the injured segment. RESULTS: On postoperative day 1, the clawing posture of the patient's hands was significantly diminished, and the patient noted an immediate improvement in his hand and arm strength. Over the next few days, the patient's strength in the bilateral upper extremities increased to motor Grade 4/5 on manual testing. A magnetic resonance image 4 weeks after decompression showed significant improvement in the cord diameter and signal. CONCLUSIONS: Post-traumatic syringomyelia has not been reported at so early a stage after injury. This disorder is an important clinical entity that must be recognized to prevent potentially fatal or devastating complications. As evidenced by the reported patient and the literature, if this disorder is discovered and treated early, permanent deficit can be avoided. The prevention of post-traumatic syringomyelia requires anatomic realignment and stabilization of the spine without stenosis, even in the case of complete injuries, to maintain the proper dynamics of cerebrospinal fluid flow.

Accidents, Occupational↗
PubMed2001

The use of neostigmine to treat postoperative ileus in orthopedic spinal patients.

Ileus is a common complication of spinal surgery, affecting 5% to 12% of all patients. Often this ileus is secondary to acute colonic pseudo-obstruction. This study is a prospective clinical trial of neostigmine in seven spinal patients with ileus after surgery to demonstrate its efficacy. All patients had evidence of the Ogilvie syndrome that was unresponsive to 24 hours of conservative therapy. Patients received 2 mg neostigmine, and abdominal circumference, clinical response, and radiographic colonic measurements were recorded. Patients were followed for recurrence of ileus for their remaining time in the hospital. Six patients had prompt colonic decompression, and no patient had recurrence of colonic distension. Side effects were minimal. These results suggest that postoperative spinal patients with ileus secondary to acute colonic pseudo-obstruction that is unresponsive to conservative therapy benefit from treatment with neostigmine, resulting in safe, rapid decompression of the colon.

Adolescent↗
PubMed2000

Influence of kinnow juice on the pharmacokinetics of sustained release theophylline in healthy male volunteers.

The effect of kinnow juice on the pharmacokinetics of a single dose of sustained release theophylline was investigated in healthy male volunteers. In a two phased open cross-over randomized study, ten healthy male volunteers were given sustained release theophylline (300 mg) along with 300 ml of water or kinnow juice, a routinely used citrus juice in India. Blood samples were collected at different time points from 0-48 hours. Plasma was assayed for theophylline by a HPLC method and various pharmacokinetic parameters were calculated and compared. The theophylline levels were lower at all the time points with kinnow juice co-administration as compared to water but were significantly so only during the absorption phase from 1-4 hours. The values for all the pharmacokinetic parameters evaluated were on the lower side with kinnow juice except Tmax which was slightly delayed. None of these alterations was found to be significantly different. The results indicate that since there is an interference with the absorption of the drug, the patients may be advised not to consume kinnow juice when taking a slow release theophylline preparation and the monitoring of plasma concentrations of theophylline in patients who routinely consume kinnow juice in their diet might be helpful in better management of these patients.

Adult↗
PubMed1999

Effect of grapefruit juice on the pharmacokinetics of theophylline in healthy male volunteers.

The effect of grapefruit juice (GFJ) on the pharmacokinetics of a single dose of theophylline was examined in an open crossover study. Healthy male volunteers were given sustained release theophylline (300 mg) along with 300 ml of either water or GFJ. Blood samples (2 ml) were collected at different time points from 0 to 48 h. Plasma was assayed for theophylline by HPLC and various pharmacokinetic parameters were calculated. Theophylline levels were lower at all time points with GFJ coadministration as compared to water but were significantly lower only during the absorption phase from 1 to 4 h. Although the pharmacokinetic parameters were not significantly different between the two groups, all values were reduced except Tmax which was slightly increased. The results indicate that patients may be advised not to consume GFJ when taking slow-release theophylline and monitoring of plasma theophylline levels in patients consuming GFJ might be helpful in better management of patient care.

Adult↗
PubMed1997

Type IV collagen is detectable in most, but not all, basement membranes of Caenorhabditis elegans and assembles on tissues that do not express it.

Type IV collagen in Caenorhabditis elegans is produced by two essential genes, emb-9 and let-2, which encode alpha1- and alpha2-like chains, respectively. The distribution of EMB-9 and LET-2 chains has been characterized using chain-specific antisera. The chains colocalize, suggesting that they may function in a single heterotrimeric collagen molecule. Type IV collagen is detected in all basement membranes except those on the pseudocoelomic face of body wall muscle and on the regions of the hypodermis between body wall muscle quadrants, indicating that there are major structural differences between some basement membranes in C. elegans. Using lacZ/green fluorescent protein (GFP) reporter constructs, both type IV collagen genes were shown to be expressed in the same cells, primarily body wall muscles, and some somatic cells of the gonad. Although the pharynx and intestine are covered with basement membranes that contain type IV collagen, these tissues do not express either type IV collagen gene. Using an epitope-tagged emb-9 construct, we show that type IV collagen made in body wall muscle cells can assemble into the pharyngeal, intestinal, and gonadal basement membranes. Additionally, we show that expression of functional type IV collagen only in body wall muscle cells is sufficient for C. elegans to complete development and be partially fertile. Since type IV collagen secreted from muscle cells only assembles into some of the basement membranes that it has access to, there must be a mechanism regulating its assembly. We propose that interaction with a cell surface-associated molecule(s) is required to facilitate type IV collagen assembly.

Animals↗
PubMed1997

Characterization of alpha1(IV) collagen mutations in Caenorhabditis elegans and the effects of alpha1 and alpha2(IV) mutations on type IV collagen distribution.

Type IV collagen is a major component of basement membranes. We have characterized 11 mutations in emb-9, the alpha1(IV) collagen gene of Caenorhabditis elegans, that result in a spectrum of phenotypes. Five are substitutions of glycines in the Gly-X-Y domain and cause semidominant, temperature-sensitive lethality at the twofold stage of embryogenesis. One is a glycine substitution that causes recessive, non-temperature-sensitive larval lethality. Three putative null alleles, two nonsense mutations and a deletion, all cause recessive, non-temperature-sensitive lethality at the threefold stage of embryogenesis. The less severe null phenotype indicates that glycine substitution containing mutant chains dominantly interfere with the function of other molecules. The emb-9 null mutants do not stain with anti-EMB-9 antisera and show intracellular accumulation of the alpha2(IV) chain, LET-2, indicating that LET-2 assembly and/or secretion requires EMB-9. Glycine substitutions in either EMB-9 or LET-2 cause intracellular accumulation of both chains. The degree of intracellular accumulation differs depending on the allele and temperature and correlates with the severity of the phenotype. Temperature sensitivity appears to result from reduced assembly/secretion of type IV collagen, not defective function in the basement membrane. Because the dominant interference of glycine substitution mutations is maximal when type IV collagen secretion is totally blocked, this interference appears to occur intracellularly, rather than in the basement membrane. We suggest that the nature of dominant interference caused by mutations in type IV collagen is different than that caused by mutations in fibrillar collagens.

Alleles↗
PubMed1997

Effect of aspartate and glutamate on nociception, catalepsy and core temperature in rats.

Effects of excitatory aminoacids (EAAs) aspartate (ASP) and glutamate (GLU) in a low (50 ng, i.c.) and high dose (20 micrograms, i.c.), were studied on nociception, catalepsy and rectal temperature in albino rats. Both ASP and GLU altered the tail flick reaction time to thermal stimulation in a dose dependent manner, increasing it with low doses and reduced with high doses. Naloxone (10 micrograms, ic) antagonized the anti-nociceptive effect of EAAs while ketamine (10 micrograms, ic)-a NMDA receptor antagonist antagonized the hyperalgesic effect. These EAAs also antagonized catalepsy induced by haloperidol, chlorpromazine, trifluoperazine and morphine. Both ASP and GLU produced a hyperthermic response in all animals, including those in which hypothermia was induced by reserpine. These EAAs produced a comparable central modulatory effects on nociception, catalepsy and core temperature.

Adrenergic Uptake Inhibitors↗
PubMed1994

Long-term effects of thrombolytic therapy on clinical course and left ventricular function after acute myocardial infarction.

Sixty five cases of Acute Myocardial Infarction, of which 40 cases received thrombolytic therapy, were followed up for a period of one year for clinical course and left ventricular function. Reperfusion was achieved in 65% cases who received thrombolytic therapy. At discharge and at one year treated group fared well on Killip Scale, and ejection fraction (EF), and the overally mortality was lower. This difference was more significant in the group who achieved reperfusion. Male sex, Anterior wall infarctions, deep Q wave infarctions as also low EF at the time of discharge and late cardiac events had adverse effect on the course of infarction during follow up.

Adult↗
PubMed1990

Effect of ascariasis upon nutritional status of children.

One hundred children aged 24-72 months who had history of passing roundworms during the preceding 12 months were compared with 100 children without such history. The two groups were matched for age, sex, economic status, and birth order. Children who had ascaris were 2.1 cm shorter in height, 0.6 cm, thinner for mid-arm circumference, and 0.38 kg lighter in weight compared to the children who did not pass ascaris. The first two of these differences were statistically significant (P less than 0.005). It is concluded that: 1. ascariasis contributes significantly to malnutrition in communities where both coexist; 2. periodic deworming should form part of community nutrition programmes in areas where ascariasis is common; 3. future studies of a similar nature should include recording of height, arm circumference, and birth order.

Arm↗