Enzyme Catalysis: Tool to Make and Break Amygdalin Hydrogelators from Renewable Resources: A Delivery Model for Hydrophobic Drugs

We report a novel approach for the controlled delivery of an antiinflammatory, chemopreventive drug by an enzyme-triggered drug release mechanism via the degradation of encapsulated hydrogels. The hydro- and organogelators are synthesized in high yields from renewable resources by using regioselective enzyme catalysis, and a known chemopreventive and antiinflammatory drug, i.e., curcumin, is used for the model study. The release of the drug occurred at physiological temperature, and control of the drug release rate is achieved by manipulating the enzyme concentration and/or temperature. The byproducts formed after the gel degradation were characterized and clearly demonstrated the site specificity of degradation of the gelator by enzyme catalysis. The present approach could have applications in developing cost-effective controlled drug delivery vehicles from renewable resources, with a potential impact on pharmaceutical research and molecular design and delivery strategies.

Predictors of mortality in mechanically ventilated patients

OBJECTIVES

There are scarce data from India validating scoring systems used to predict outcome in patients requiring mechanical ventilation. This study prospectively compared the organ system failure (OSF), the acute physiology and chronic health evaluation (APACHE) II, and the APACHE III, scores on patients requiring mechanical ventilation in the medical intensive care unit, to predict outcome.

METHODS

200 consecutive patients requiring mechanical ventilation in a medical intensive care unit were recruited. OSF, APACHE II, and APCHE III scores were calculated at admission and daily for one week or until discharge in all patients. Other variables recorded include age, sex, diagnosis, oxygen therapy before ventilation, complications on ventilation, duration in hospital before ventilation, duration of ventilation, type of respiratory failure, alveolar arterial oxygen gradient, P/F ratio, use of tracheostomy, time on ventilator before tracheostomy, muscle relaxant used, fluid balance, inotrope support. Logistic regression analysis and area under the curve were computed to determine which variables independently predict outcome.

RESULTS

Of the 200 patients, at discharge 143 patients (71.5%) had died. The factors that independently predicted outcome among these patients on mechanical ventilation were the type of respiratory failure (type I) OR = 2.7 (p = 0.02), the use of inotropes OR 2.4 (p = 0.04), and the APACHE II score OR = 1.8 (p = 0.008) for every five point increase in APACHE II score.

CONCLUSIONS

Type 1 respiratory failure, the use of inotropes, and the APACHE II score measured at admission are significant independent predictors of mortality in the patients on mechanical ventilation.

Smart amphiphiles: hydro/organogelators for in situ reduction of gold

New urea containing gels have been used to prepare and stabilise gold nanoparticles by in situ reduction.

Primary carcinoid tumour of the testis

A left radical orchidectomy was performed on a 32-year-old man presenting with a testicular mass. Histology revealed a tumour comprising of cells with monotonous nuclei and granular cytoplasm arranged in an insular pattern. Immunohistochemical expression for NSE, synaptophysin and chromogranin A were positive. No teratomatous elements were seen. Postoperatively, a staging CT and an octreotide scan were normal. Urinary 5-HIAA levels were not elevated. Based on these investigations the tumour was diagnosed as a pure primary carcinoid tumour of the testis. The patient has been followed up for 3 years with no evidence of recurrence.

Predictors of multi-organ dysfunction in heatstroke

BACKGROUND

Heatstroke is a medical emergency that results from failure of thermoregulatory mechanism coupled with an exaggerated acute phase response, causing an elevation in core body temperature that rises above 40 degrees C, producing multi-organ dysfunction. It carries a high mortality rate, and in survivors, a risk of permanent neurological damage.

OBJECTIVE

To investigate predictors of multiple organ dysfunction syndrome in patients presenting with heatstroke.

METHODS

We investigated 28 patients admitted to a hospital in southern India during the period January 1998 to December 2001. Using a standard form, we collected data on the patients' characteristics, laboratory data, and outcome, and compared those with multiple organ dysfunction with those without such dysfunction.

RESULTS

We found that more than three quarters of the studied patients developed multiple organ dysfunction, with the most common dysfunction being respiratory failure. Among the selected predictors, metabolic acidosis 14 of 16 patients, 87.5%; p = 0.011, elevated CPK 17 of 19 patients, 89.5%; p = 0.005, and liver enzymes elevated more than twice the normal (11 of 18 patients, 61%; p = 0.02) had the highest correlation with dysfunction of two or more organs.

CONCLUSIONS

The high mortality observed in heatstroke is secondary to multi-organ dysfunction, and among the various parameters assessed, high levels of CPK (>1000 IU/l), metabolic acidosis, and elevated liver enzymes are predictive. Aggressive measures to lower the body temperature with other supportive therapy could substantially reduce the mortality.

An unusual scrotal lump

Polyorchidism is a rare anomaly of the genital tract in which supernumerary testes are present, usually within the scrotum. Less than 100 cases have been reported in the literature. We present a case of polyorchidism in which the diagnosis was made on ultrasonography and as there was no evidence of an associated pathology on clinical examination or imaging, surgical exploration was therefore not considered necessary.

Local environment and property of water inside the hollow cylinder of a lipid nanotube

We investigated the local environment of water confined inside the hollow cylinder of lipid nanotubes (LNTs) by time-resolved fluorescent measurements and attenuated-total-reflectance infrared (ATR-IR) spectroscopy. The LNT was obtained by self-assembly of cardanyl glucosides in water at room temperature and had an open-ended cylindrical nanospace with a diameter of 10-15 nm, a length of 10-100 microm, and hydrophilic inner and outer surfaces. We introduced a fluorescent probe of 8-anilinonaphthalene-1-sulfonate into the confined water and observed an extremely slow dynamic Stokes shift with a correlation time of 1.26 ns, which was 2-3 orders of magnitude longer than that of bulk-phase water. From the peak shift of the fluorescent spectrum, the local solvent polarity (ET(30)) of the confined water was estimated as 50 kcal/mol, which is 20% lower than that in bulk water. ATR-IR measurements showed that the hydrogen-bond network of water inside the LNT was more developed than that in bulk water at room temperature, which is in contrast to the water in other self-assembled confined geometries, such as Aerosol-OT (AOT) reversed micelles.

Lipid-Based Nanotubes as Functional Architectures with Embedded Fluorescence and Recognition Capabilities

A limited combinatorial strategy was used to synthesize a small library of soft lipid-based materials ranging from structurally unordered fibers to highly uniform nanotubes. The latter nanotubes are comprised of a bilayer structure with interdigitated alkyl chains associated through hydrophobic interactions. These tubes contain accessible 2,6-diaminopyridine linkers that can interact with thymidine and related nucleosides through multipoint hydrogen bonding, thereby quenching the intrinsic fluorescence of the aromatic linker. These results are the first example of a systematic strategy to design functional lipid nanotubes with precise structural and functional features.

Unsaturation effect on gelation behavior of aryl glycolipids

Structurally simple, renewable-resource-based cardanyl (glucoside)s [1, 1-O-3'-n-(pentadecyl) phenyl-beta-D-glucopyranoside; 2, 1-O-3'-n-(8'(Z)-pentadeceenyl)-beta-glucopyranoside; 3, 1-O-3'-n-(8'(Z),11'(Z)pentadecadienyl)phenyl-beta-D-glucopyranoside, 4; 1-O-3'-n-(8'(Z),11'(Z),14'-pentadecatrienyl)phenyl-beta-D-glucopyranoside; and the mixture 5] form thermally reversible transparent gels in a water/alcohol mixture and a number of organic solvents, strongly influenced by the unsaturation of the aliphatic alkyl chain. DSC studies revealed that the Tgel of 1 in water/ethanol (1:1, vol/vol) gel is 69.0 degrees C, while of the introduction of a single double bond reduces the value to 30.0 degrees C in the case of monoene 2, indicating that the stability of the gel is related to the number of double bonds on the lipophilic part of the gelator. Furthermore, XRD measurements showed that the aqueous gel 1 maintains an interdigitated bilayered structure with 3.14 nm long-range ordering, and the corresponding organogel maintains an extended bilayer structure for 4.34 nm, indicating a clear difference in the aggregation behavior in different solvents.

Drug resistant tuberculosis in diabetes mellitus: a retrospective study from south India

This study was conducted in a tertiary care teaching hospital in south India to evaluate the association of drug resistant tuberculosis (TB) in diabetic subjects. There were: 361 subjects with positive mycobacterial culture and susceptibility tests results over a 3-year period; 267 (74%) acid-fast bacillus smear positive; and 94 (26%) smear negative cases. One hundred and seventy-seven (49%) had resistant isolates to any one first line antiTB drugs (resistant group) and 184 (51%) had isolates sensitive to all drugs (non-resistant group). In the resistant and non-resistant subjects the mean duration of TB symptoms was, respectively, 22 months and 4.5 months, past history of TB 126 (71%) and 48 (26%), past antiTB drug therapy 126 (71%) and 47 (25%), inadequate anti TB drug therapy 42 (24%) and 23 (13%), HIV positive six and 13 subjects. There were 72 diabetic subjects [35 and 37, respectively] with a duration of diabetes 5.8 +/- 7.5 years and 3.7 +/- 5.0 years in the resistant and non-resistant groups. Twenty-six per cent of the diabetic subjects (19/72) had multi-drug resistantTB. Drug resistance to first line anti-TB drugs was not found to be associated with diagnosis or duration of diabetes mellitus.

Clinical characteristics and treatment response among patients with multidrug-resistant tuberculosis: a retrospective study

BACKGROUND

This retrospective study was conducted to evaluate the characteristics and therapeutic response among patients with multidrug-resistant tuberculosis (MDR TB).

METHODS

One hundred subjects with isolates resistant to isoniazid and rifampicin were included over a three-year period (1997-1999). There were 82% males with a mean age of 36 years, mean duration of symptoms of 29 months, and a previous history of tuberculosis in 85% (pulmonary 96% and extrapulmonary 4%).

RESULTS

HIV ELISA test was positive in two out of 28 (7%) patients while diabetes was diagnosed in 16 percent. Mean time to diagnose MDR TB was 5.5 months. Subjects had received a mean of 3.2 anti-TB drugs before the diagnosis of MDR TB was made. Forty-five patients were lost to follow-up. The rest had a median follow-up of 13.5 months (range 1-37 months). Follow-up AFB smear and culture results were available in 49 out of 55 and 26 out of 55 patients, respectively. Sputum smear became negative for AFB in 26 out of 49 (53%) and culture converison occurred in 16 out of 26 (61.5%) patients. Clinical and radiological response was noted in 31 (56%) and 13 (32.5%) out of 40 patients respectively. A mean of 5.5 drugs was used in those who achieved sputum conversion. Combination therapy containing ofloxacin in the regimen was noted to have a favourable response.

CONCLUSION

Only a limited number of patients with MDR tuberculosis have a favourable response.